One Day or Two?
Many years ago, when first living in Yerushalayim, I needed to stay in the hospital over Sukkos. Although being stuck in a hospital for Yom Tov is never an ideal situation, on the other hand, with minyanim, Mehadrin food, and a place for visitors to sleep, Shaare Zedek Hospital is still probably the best case scenario for a frum Yid in need.
However, Motzai Yom Tov is another story altogether. The hospital fully switches back to weekday mode. Yet, as a recent American expatriate who just temporarily moved to Eretz Yisrael, I was in a true bind. For me, seemingly the only one in the entire hospital complex, it was now Yom Tov Sheini. Yet for the entire hospital staff, it was already Isru Chag. The Israeli doctors and nurses could not figure out why I couldn’t just drive home to sleep, take the elevator or even turn on a light, now that Yom Tov was over.
Luckily, my dilemma was noticed by the legendary Reverend Asher Hirsch a”h, Shaare Zedek’s indefatigable resident Chazzan, Gabbai, and coordinator of spiritual matters, who came to my aid, graciously allowing me use of his office for the night. He also gave me a piece of advice, mostly in jest, with a twinkle in his eye. “Your problem is not that you asked the wrong question. It’s that you asked the wrong rabbi. Next time you are in such a situation, I recommend asking a Chabad or Sefardic rabbi.”
This article sets out to explore why the “type of rabbi” should change the solution to my Yom Tov / Weekday quandary.
To properly understand this, some Jewish History is in order, dating back several millennia. As long as the Sanhedrin in Eretz Yisroel established the New Month (Rosh Chodesh) based on eyewitnesses, Jews in far away places that did not receive messengers in time to tell them when the Rosh Chodesh was declared would keep two days of Yom Tov instead of one. This was due to the uncertainty about which day Rosh Chodesh truly was and consequently when the Yomim Tovim actually fell out. This was done in order to ensure that no one should unwittingly transgress any Biblical prohibitions. Later, when much calendar confusion reigned due to the subversive efforts of the Kutim (as detailed in Mishnayos Rosh Hashanah Ch. 2, Mishnah 2 and following Gemara), Chazal decreed that in Chutz La’aretz, “Yom Tov Sheini”, or a two-day Yom Tov, instead of the Biblically mandated one day, must be observed. Rav Hai Gaon maintained that this Takanah actually dates to the times of Yechezkel and Daniel, and possibly even Yehoshua bin Nun, while Rav Saadiah Gaon held it was halachah l’Moshe M’Sinai.
“Fine”, one might respond, “but that was before we had a set calendar. Nowadays is there any reason to observe two days of Yom Tov?”
Not a recent difficulty, the Gemara itself (Beitzah 4b) actually asks this most common question regarding “Yom Tov Sheini”: ‘But now that we have a set calendar and we know in advance when Rosh Chodesh will be, why must we still observe a “two-day Yom Tov”?’The Gemara answers that in the times of Rabbi Elazar ben Pedas a message was sent from the Rabbanim of Eretz Yisroel to the Diaspora: “Hizharu B’Minhag Avoseichem B’Yadeichem”, ‘You should still be vigilant with the custom of your forefathers that has been handed down to you (meaning that they must still keep “Yom Tov Sheini”) because there might be times when the local government will issue a decree and it will cause confusion”.
This is not the only time that such a communiqué was sent from Eretz Yisroel to Chutz La’aretz mandating them to keep ‘Yom Tov Sheini’. In fact, the Yerushalmi records a similar occurrence, that after Chazal found out about a specific incident in Alexandria, Rabbi Yosi (bar Zavda) sent out a message that even though there was a set calendar (‘shekasvu lachem sidrei Mo’ados’), still, “al tishnu Minhag Avoseichem”, “Do not deviate an iota from the custom set by your forefathers”, and observe ‘Yom Tov Sheini’. Chazal were extremely strict with this Takana and even put someone in Cherem (excommunication) for violating this decree (see Gemara Pesachim 52a).
The outcome of this has long since become a famous dichotomy: in Eretz Yisroel where there never was a safek yom or “day in doubt”, since messengers would always be able to reach every community throughout Eretz Yisroel in time for Yom Tov, only one day of Yom Tov is celebrated, exactly as it is written in the Torah, while in Chutz La’aretz each day of Yom Tov of the Shalosh Regalim has long since become a “two-day Yom Tov”.
This author realizes that at this point readers in Israel are probably saying that this is all very nice, but this doesn’t affect them; they only keep one day. “No safek yom here.” But actually it just might concern them. For what is a “Chutznik” or two-day Yom Tov keeper who happens to be in Israel for Yom Tov (quite commonly yeshiva bochurim) to do?
Although the famed Chacham Tzvi, and later the Shulchan Aruch Harav, ruled that even one merely visiting Eretz Yisrael over Yom Tov should keep only one day of Yom Tov like the natives (to paraphrase: ‘when in Israel, do as the Israelis do’), nevertheless, the vast majority of halachic authorities, including the Shulchan Aruch himself and even the Chacham Tzvi’s own son, Rav Yaakov Emden, maintained that vistors’ status is dependant on whether or not their intention is to stay and live in Eretz Yisrael, or to return to Chutz La’aretz, known as ‘im da’atam lachzor’.
This dictum is based on Gemara Pesachim (51a - b) regarding Rabba Bar Bar Chana, Rav Ashi, and Rav Safra. As elucidated by the Shulchan Aruch in his responsa (Shu”t Avkas Rochel 26), anyone who has Da’as Lachzor, intention to return, maintains his original status as if he were still in the place from ‘whence he came’.
Practically, this means that if one is planning on living in Eretz Yisrael he would keep only one day of Yom Tov. Correspondingly, if planning on returning to Chutz La’aretz, one must still observe a two-day Yom Tov, even while currently staying in Eretz Yisrael.
Defining Da’as Lachzor
Although this streamlines the issue somewhat, nevertheless, how the poskim define ‘da’atam lachzor’ is not so simple and may vary from Posek to Posek and each individual situation needs to be taken into account.
Classically, there are several important factors that are taken to account to be able to be koveya, or establish, one’s status as a Ben Eretz Yisrael or a ‘Chutznik’.
Family: A late Rishon / early Acharon, the Radbaz, wrote that if one moved with his wife (and children), even if planning on returning, he loses his status of Da’as Lachzor, as that creates a new kevuyus of presence. In other words, such a move, uprooting one’s family and settling in Eretz Yisrael, even if meant temporarily, nonetheless turns him into a Ben Eretz Yisrael and only one day of Yom Tov need be kept.
Although the Radbaz’s halachic precedent is widely cited, on the other hand, many contemporary authorities argue that nowadays with the advent of air travel, when one can be in and out of Eretz Yisrael within several hours, as opposed to the months-long travel by sea in the Radbaz’s day, this reasoning alone should no longer be enough to establish a keviyus makom.
- Purpose: The Pri Chodosh argues on the Radbaz’s premise that family is the only deciding factor in status setting. He differentiates between the purpose of the trip. If one brings his family to Eretz Yisrael on a Kevarim Tour for example, then even if staying for Yom Tov, he certainly would still keep two days. Yet, if he brought his family in order to be able to make a living, a proper parnassah, then even if planning on returning, he would keep only one day.
Time: Although the Pri Chodosh and other poskim do not distinguish between a shorter or longer trip, there are poskim, including the Aruch Hashulchan and Avnei Nezer, who set the time limit at one year. This would mean that if one stayed in Eretz Yisrael for a full year, even while intending to return to Chutz La’aretz, he is nevertheless considered a Ben Eretz Yisrael. Some cite support for this view from the Mishnah inBava Basra (7b), that one is considered a city resident after 12 months.
Some make a distinction whether staying for a set time while planning to return afterwards, (for example, a 3-year job), that it is still considered Da’as Lachzor.
On the other hand, many others hold that time should not be a factor at all, and one may be living in Eretz Yisrael for 5 or even 10 years and still be keeping two days of Yom Tov if they are still planning on returning.
- Bachelorhood: There is an interesting opinion cited by the Chida, and ruled accordingly by many Sefardic poskim, that a bochur who is eligible to get married should keep one day of Yom Tov in Eretz Yisrael. This is due to the idea that if a good shidduch suggestion with a local girl would come up, he would certainly agree and stay permanently in Eretz Yisrael. Therefore, he would already now be considered a Ben Eretz Yisrael. Others, mainly Ashkenazic authorities, disagree, maintaining that as a Bochur’s entire livelihood is dependant on his parents in Chutz La’aretz, his single status should therefore not be a deciding factor.
Come what may, we see that there are many issues taken into account before a Rav or Posek can issue a final psak in the matter, and it will be entirely dependant on and according to each person’s individual situation.
Different Strokes for Different Folks
Back at the hospital, why did Revered Hirsch a”h wryly suggest asking a Chabad or Sefardic rabbi whether one should keep one day or two in Eretz Yisrael?
This is due to the fact that they often recommend a ‘Chutznik’ observing only one day in Eretz Yisrael, albeit for very different reasons. Chabad chassidim generally follow the shittah of their Alter Rebbe, the Shulchan Aruch Harav, ruling akin to the precedent of the Chacham Tzvi, and only keep one day in Eretz Yisrael, no matter how short or how long they intend on staying.
Contrastingly, Sefardic poskim follow the dictum of ‘im da’atam lachzor’. Yet, they generally define it differently than many of their Ashkenazic counterparts. For example, Rav Ovadiah Yosef zt”l and Rav Ben Tzion Abba Shaul zt”l both ruled that certainly one who has stayed in Eretz Yisrael for a year should now keep only one day of Yom Tov. Additionally, they maintain a bochur of marriageable age should also observe Yom Tov similarly. Therefore, Sefardic poskim are perceived as being ‘more meikil’ in these matters.
That is why when I was stuck in a hospital where everyone was exclusively observing one day of Yom Tov, this ‘Chutznik’ was ‘prescribed’ to ask for a ‘second opinion’.
Note: This article is not intended to serve as an exhaustive guide, but rather to showcase certain aspects of the intricate and myriad halachos of Yom Tov Sheini. As with all matters in halachah, one should ascertain from his own halachic authority the proper ruling for his own personal situation.
This author wishes to acknowledge Rabbi Yerachmiel Dovid Fried’s classic sefer Yom Tov Sheini Kehilchaso, as it which contains a wealth of information on the parameters of Yom Tov Sheini and has been extremely useful in writing this article.
This article was written l’zechus for Shira Yaffa bas Rochel Miriam v’chol yotzei chalatzeha for a yeshua sheleimah teikif umiyad.
For any questions, comments or for the full Mareh Mekomos / sources, please email the author: email@example.com.
Rabbi Yehuda Spitz serves as the Sho’el U' Meishiv and Rosh Chabura of the Ohr Lagolah Halachah Kollel at Yeshivas Ohr Somayach in Yerushalayim. Author of the recent sefer M’Shulchan Yehuda on Inyanei Yoreh Deah, he also currently writes a contemporary halachah column for the Ohr Somayach website titled “Insights Into Halachah”.
 See Rambam (Hilchos Kiddush HaChodesh Ch. 3: 11 & Ch. 5: 4).
 See Gemaras Beitzah 4b and Rosh Hashanah 21a (and commentaries), Yerushalmi Rosh Hashanah (Ch. 2, Halachah 1), Shu”t HaGaonim Lik (1; referenced in Sha’ar HaTziyun 496, 1), Rambam (Hilchos Kiddush HaChodesh Ch. 5: 6), Sefer Hachinuch (Parshas Emor, Mitzva 301; and Minchas Chinuch ad loc.), Tur and Shulchan Aruch and main commentaries to Orach Chaim 496, Magen V’Tzina (pg. 7b), Kuzari Hasheini (Matteh Dan, pp. 83 & 241), Maharitz Chiyus (Darchei Hora’ah ppg. 7 - 8), Chasam Sofer (Beitzah 4b), Tiferes Yisroel (Mishnayos Ediyos Ch. 1, Mishnah 6: 35), Rav Yisroel Moshe Chazzan’s ‘Kedushas Yom Tov’, Shu”t Yad Eliezer (131), Shu”t Shaar Asher (Orach Chaim 8), Sdei Chemed (vol. 6, Ma’areches Yom Tov 2, 8), Chazon Ish (Moed, Hilchos Yom Tov, Orach Chaim 130), Rav Yechiel Michel Tukachinsky’s Ir HaKodesh V’HaMikdash (Vol. 3, Chapters 18 & 19), and the forward to Rabbi Yerachmiel Dovid Fried’s classic sefer Yom Tov Sheini Kehilchaso at length. See also Meshech Chochma (Parshas Bo, Beginning of Ch. 12, s.v. uvazeh) who offers a compelling reason why ‘Yom Tov Sheini’ still applies nowadays - ‘gezeira shema yivneh Bais HaMikdash’.
 Rashi (ad loc. s.v. d’gazri) clarifies that this is referring to calendar confusion. He explains that the government will decree against learning Torah and the ‘sod haIbur’ (the principle of the intercalation of the New Month) will be forgotten, and if Klal Yisroel reverts to keeping one day of Yom Tov, they might establish a ‘Chasar’ month as a ‘Malei’ or vice versa, and they will possibly (Chas V’Shalom) end up eating Chametz on Pesach. Although the Gemara does not specify which Amora sent this message, nor to which community in Chutz La’aretz it was sent, nevertheless, the Gemara’s unique choice of phraseology “shalchu mesum”, clues us in that it denotes a message sent by Rabbi Elazar ben Pedas, as explained in Gemara Sanhedrin (17b) and Rashi’s commentary to Gemara Shabbos (19b s.v. R’ Elazar). See Ir HaKodesh V’HaMikdash (vol. 3, Chapter 19, 1). [Interestingly, the Meiri (Beis Habechira on Sanhedrin ad loc.) has a different Girsa in the Gemara; he quotes the expression “shalchu mesum” as indicating a missive from Rabbi Yirmiya] See also Shu”t Goren Dovid (Orach Chaim 41) who utilizes the infamous 1242 burning of 24 wagonloads of Gemaros and Kisvei Rishonim in France [as detailed at length in previous article titled “Forgotten Fast Days: Zos Chukas HaTorah”] as a reason to explain why nowadays Yom Tov Sheini is still observed. Unfortunately, throughout our long and bitter Golus we never know when a government might make a gezeirah ra’ah and consequently all halachic literature lost. How then will we be able to properly calculate the months and years to know when are the correct days to observe? He explains that this tragedy was a fulfillment of the Gemara’s warning to keep Yom Tov Sheini, “Hizharu B’Minhag Avoseichem B’Yadeichem”.
 Yerushalmi (Eruvin Ch. 3, end Halachah 9; see also Korban Haeidah ad loc.).
 Even though the messengers of Tishrei and Nissan would certainly have reached even far flung places by Shavuos, nevertheless, Chazal still established a Yom Tov Sheini for Shavuos, in order not to make a distinction between the Yomim Tovim. See Rambam (Hilchos Kiddush HaChodesh Ch. 3: 12), Shu”t Chasam Sofer (Orach Chaim 146 and Yoreh De’ah 252), Shu”t Sho’el U’Meishiv (Mahadura Tinyana vol. 2: 85 s.v. v’hinei l’fan”d) and Shu”t Machazeh Avrohom (Orach Chaim 121). See also Chiddushei Maran Ri”z HaLevi al HaTorah (Parshas Emor); the Brisker Rav zt”l notes that the exact date of Shavuos is always already set from the beginning of Nisan, as the pasuk states regarding Shavuos (Parshas Emor Ch. 23: 21) that it is observed “b’etzem hayom hazeh”, hence keeping it as a two-day Yom Tov is also considered a Takanah of sorts.
 This, as well as why Rosh Hashanah remains two days even in Eretz Yisrael, was discussed at length in a previous article titled ‘Rosh Hashanah: The Universal Two-Day Yom Tovand Why Yom Kippur Is Not’.
 Shu”t Chacham Tzvi (167) and Shulchan Aruch Harav (Orach Chaim 496: 11; although he also cites that ‘yesh cholkim’, nonetheless, this first opinion is ikar - see also vol. 1, Mahadura Tinyana 68). This shittah is also defended by the Aderes (Sefer Shevach Ha’aretz, 35) and Shoel U’Meishiv (Shu”t Mahadura Telitai vol. 2: 28) and heavily implied by the Avnei Nezer (Shu”t Orach Chaim 242: 27 and 33; 539: Hashmatos to Hilchos Yom Tov, 48 - end; he maintains that ‘da’atam lachzor’ should not apply even for visitors from Eretz Yisrael who are staying in Chutz La’aretz over Yom Tov). This shittah has also found support in certain Rishonim, including Rabbeinu Chananel’s understanding of Rav Safra’s opinion (Pesachim 51b - 52a), and the Ra’avan (Pesachim 162: 2; see Even Shlomo’s commentary 37). Although, as shown later on, most contemporary authorities do not rule this way, nonetheless, Chabad chassidim generally follow the shittah of their Alter Rebbe, the Shulchan Aruch Harav, and only keep one day in Eretz Yisrael, no matter how long they intend on staying. Rav Yechiel Michel Tukachinsky (Ir HaKodesh V’Hamikdash vol. 3, Ch. 19: 8) reports that his grandfather-in-law, the Av Beis Din of Yerushalayim for the latter part of the nineteenth century, Rav Shmuel Salant zt”l, was notteh to this shittah as well. However, since he did not want to argue on his Rabbeim, including the Pe’as Hashulchan (see next footnote), who mandated visitors keeping Yom Tov Sheini, Rav Salant ruled that a Ben Chutz La’aretz should keep both days lechumrah (a shittah now commonly referred to as ‘A Day and a Half’ - see also Nefesh HaRav pg. 84). For more on Rav Shmuel’s shittah see the Tukachinsky Luach Eretz Yisrael (Shemini Atzeres, footnote), Shu”t Lehoros Nosson (vol. 11: 26), Toras Rabbeinu Shmuel Salant (pg. 120), and Aderes Shmuel (Piskei Rav Shmuel Salant zt”l; Hilchos Yom Tov 129, and in footnotes at length, ppg. 131 - 135).
 Although there are those who want to prove that the Shulchan Aruch meant to rule that a visitor to Eretz Yisrael should only keep one day, as in the Shulchan Aruch (Orach Chaim 496) he only mentions visitors from Eretz Yisrael in Chutz La’aretz, who need to keep a two-day Yom Tov like the locals, nevertheless, he personally put that notion to rest in his Shu”t Avkas Rochel (26), where he explicitly ruled that the Yom Tov observance of visitors to Eretz Yisrael is dependant on whether they are planning on staying or not. Other poskim who rule this way include the Rav Yaakov Emden (Shu”t Sheilas Ya’avetz vol. 1: 168), the Pe’as Hashulchan (Hilchos Eretz Yisrael 2: 15, 21), the Chida (Shu”t Chaim Sha’al vol. 1: 55, and Birkei Yosef, Orach Chaim 496: 7), Mahar”i Chagiz (Shu”t Halachos Ketanos vol. 1: 4), the Pri Ha’adamah (vol. 3, pg. 17b; citing ‘kol Rabbanei Yerushalayim’), Shaarei Teshuvah (496: end 5; he makes a sikum of the shittos), Chayei Adam (vol. 2, 103: 4), Aruch Hashulchan (Orach Chaim 496: end 5), Mishnah Berurah (ad loc. 13), Kaf HaChaim (ad loc. 38), and Rav Yechiel Michel Tukachinsky (Ir HaKodesh V’Hamikdash vol. 3, Ch. 19: 8). The vast majority of contemporary poskim rule this way as well. See Shu”t Igros Moshe (Orach Chaim vol. 3: 73 and 74 and vol. 4: 101), Orchos Rabbeinu (new print - 5775 edition, vol. 2, Ch. ‘Yom Tov Sheini’; citing the Chazon Ish and Steipler Gaon), Shu”t Seridei Aish (new edition; vol. 1, Orach Chaim 51: 1), Shu”t Minchas Yitzchak (vol. 4: 1 - 4), Yom Tov Sheini Kehilchaso (pg. 108, footnote 5; citing many Rabbanim including the Tchebiner Rav, Rav Shlomo Zalman Auerbach, Rav Yosef Shalom Elyashiv, and Rav Chaim Pinchas Scheinberg, whose teshuvah is printed in the back of the sefer), Shu”t Shevet Halevi (vol. 5: 64), Shu”t Mishnah Halachos (vol. 4: 83), Shu”t Tzitz Eliezer (vol. 9: 30), Halichos Even Yisrael (pg. 287 - 288), Shu”t Yaskil Avdi (vol. 4, Orach Chaim 26), Shu”t B’tzeil Hachochmah (vol. 1: 60), Shu”t Yabea Ome r (vol. 6, Orach Chaim 40: 1 - 3), Shu”t Ohr L’Tzion (vol. 3: Ch. 23: 5), Shu”t Knei Bosem (vol. 1: 28), Chazon Ovadia (Yom Tov, pg. 133: 12), and Yalkut Yosef (Moadim, pg. 460).
 Although many Rishonim each understand this Gemara differently, nonetheless the Shulchan Aruch and other Acharonim, including the Radbaz (Shu”t vol. 4: 73 or 1145; depending on edition), Magen Avrohom (Orach Chaim 496: 7), Shach (Yoreh Deah 214: 8), and Pri Chodosh (Orach Chaim 466 and 468), follow the explanation of Tosafos, Rosh, and Ran (Pesachim ad loc.), that the defining factor is indeed ‘im da’atam lachzor’. See previous footnote.
 See at length Kaf Hachaim (Orach Chaim 496: 38 - 59) and Yom Tov Sheini Kehilchaso (Ch. Keveeyus Sheim Ben E”Y U’Ben Chu”l, ppg. 156 - 208).
 Radbaz (Shu”t vol. 4: 73 or 1145; depending on edition), cited by Magen Avrohom (Orach Chaim 496: 7), Pri Chodosh (Orach Chaim 466 and 468),Knesses Hagedolah (Orach Chaim 496), Elyah Rabbah (ad loc. 6), Maharikash (ad loc.), Shulchan Aruch Harav (ad loc. 10), Shaarei Teshuvah (ad loc. 5), Ba’er Heitiv (ad loc. 5), Chayei Adam (vol. 2, 103: end 4), Aruch Hashulchan (Orach Chaim 496: 5), and Mishnah Berurah (496: 13), among others. Several contemporary poskim follow the Radbaz’s shittah nowadays as well, especially in conjunction with the Aruch Hashulchan’s opinion of staying for more than a year (see footnote 14); meaning if one moved with his family and stayed for a year, that should be sufficient to change his status to ‘ain da’as lachzor’. See Shu”t Tzitz Eliezer (vol. 9: 30), Shu”t Seridei Aish (new edition; vol. 1, Orach Chaim 51: 1 s.v. v’ayeni), Shu”t Yaskil Avdi (vol. 4, Orach Chaim 26), Shu”t Knei Bosem (vol. 1: 27), and Shu”t Yechaveh Daas (vol. 3: 35).
 See Shu”t Igros Moshe (Orach Chaim vol. 3: 74), Orchos Rabbeinu (new edition - 5775; vol. 2, pg. 140: 1; citing the Steipler Gaon), Shu”t Shevet Halevi (vol. 5: 64), Rav Chaim Pinchas Scheinberg’s teshuvah printed at the end of Yom Tov Sheini Kehilchaso, Shu”t Ohr L’Tzion (vol. 3: Ch. 23: 5), and Yom Tov Sheini Kehilchaso (pg. 162 - 163), citing Rav Shlomo Zalman Auerbach and Rav Yosef Shalom Elyashiv.
 Although the Mishnah Berurah (Shaar Hatziyun 496: 19) seemingly understands the Pri Chodosh (Orach Chaim 468: 4 s.v. v’ra’isi) to be elucidating the Radbaz’s opinion, many contemporary authorities differ, explaining that he was essentially arguing with the Radbaz’s position. See Shu”t Seridei Aish (new edition; vol. 1, Orach Chaim 51: 1 s.v. v’ayen), Shu”t Tzitz Eliezer (vol. 9: 30), Chazon Ovadia (Yom Tov, pg. 122 s.v. amnam), and Yom Tov Sheini Kehilchaso (pg. 162, footnote 27).
 See Aruch Hashulchan (Orach Chaim 496: 5), Shu”t Avnei Nezer (Orach Chaim 424: 28 and 30), Shu”t Shevet Halevi (vol. 5: 64), Shu”t Tzitz Eliezer (vol. 9: 30), Shu”t Seridei Aish (new edition; vol. 1, Orach Chaim 51: 1 s.v. v’hinei), Shu”t Ohr L’Tzion (vol. 3: Ch. 23: 8), Shu”t Yechaveh Daas (vol. 3: 35), and Yalkut Yosef (Moadim pg. 461 - 462).
 See Shu”t Mishnah Halachos (vol. 4: 83). The Chida (Shu”t Chaim Sha’al vol. 1, Orach Chaim 55) implies this way as well. Rav Ovadiah Yosef (Shu”t Yechaveh Daas ibid. and Chazon Ovadiah on Yom Tov, pg. 121 and 25 - 126) strongly argues that from the words of many poskim, including the Yaavetz (Shu”t Sheilas Yaavetz vol. 1: 168 s.v. u’v’inyan), and the Maharit Tzahalon (Shu”t 52), once one is living overseas, and certainly after a year, he is no longer considered ‘da’as lachzor’ no matter if he only left for a set, limited amount of time.
 This shittah follows the basic understanding of the Pri Chodosh, that the ikar follows ‘da’as lachzor’, with no regard to amounts of time. See Shu”t Zera Avrohom (vol. 1, Orach Chaim 12), Shu”t Igros Moshe (Orach Chaim vol. 3: 75), Orchos Rabbeinu (new edition - 5775; vol. 2, pg. 139 - 140: 10; citing the Chazon Ish averring that the Radbaz’s shittah has no mekor in the Gemara), Shu”t Minchas Yitzchak (vol. 4: 1 - 4), Shu”t B’tzeil Hachochmah (vol. 1: 60), Shu”t Knei Bosem (vol. 1: 28), Rav Chaim Pinchas Scheinberg’s teshuvah printed at the end of Yom Tov Sheini Kehilchaso, and Yom Tov Sheini Kehilchaso (pg. 159 - 161 and footnotes 18 and 23), citing Rav Shlomo Zalman Auerbach and Rav Yosef Shalom Elyashiv. Rav Elyashiv’s shittah is a bit more nuanced, as he maintains that one cannot predict what his intentions are 10 years ahead (see ad loc. footnote 25 s.v. v’shama’ati).
 See Shu”t Chaim Sha’al (ibid.), Rav Chaim Fala’ji’s Ruach Chaim (496), Shu”t Ohr L’Tzion (vol. 3: Ch. 23: 5), Shu”t Yechaveh Daas (vol. 1: 26), Shu”t Yabea Omer (vol. 6: Orach Chaim 40), Chazon Ovadia (Yom Tov, pg. 139 and on: 14), and Yalkut Yosef (Moadim pg. 460: 3). Interestingly, the Avnei Nezer (Shu”t Orach Chaim 424: 30 and 33) rules similar, but for a different reason. He questions the Maharil and Magen Avrohom’s assessment regarding Bochurim away from home for several years (see next footnote), and concludes lishitaso, that after 12 months Bochurim are now considered Bnei Ir of where they are learning. There is an amusing anecdote told of Rav Ovadiah Yosef zt”l, that a ‘Chutznik’ Bochur asked him if he should sit in the Sukkah on Shemini Atezeres in Eretz Yisrael. Rav Ovadiah replied “Pattur”, explaining that a Bochur might get married and stay in Eretz Yisrael and therefore should be considered a Ben Eretz Yisrael. The Bochur demurred, maintaining that there is absolutely no possibility that he will stay in Eretz Yisrael. “Even if I personally arrange a proper shidduch for you?” asked the Sefardic Gadol. “Yes”, insisted the stalwart Bochur. “Even if said Shidduch is with my daughter?” “Yes”, averred the Bochur emphatically. “Well, if so, then you are still Pattur, because you would be categorized as a Shotteh, who is Pattur from Mitzvos”.
 See Magen Avrohom (468: 12) citing the Maharil’s case ofBochurim learning far away from home, that they are considered ‘da’atam lachzor’even though they stay for two or three years, Shu”t Sheilas Yaavetz (vol. 1: 168), Shu”t Igros Moshe (Orach Chaim vol. 2: 101), Shu”t Chelkas Yaakov (vol. 3: 154), Halichos Even Yisrael (pg. 288: 24), and Yom Tov Sheini Kehilchaso (pg. 199, footnote 7), citing Rav Shlomo Zalman Auerbach and Rav Yosef Shalom Elyashiv.
 Shu”t Yechaveh Daas (vol. 3: 35), Chazon Ovadia (Yom Tov, pg. 122 - 123), and Shu”t Ohr L’Tzion (vol. 3: Ch. 23: 8). Rav Ben Tzion Abba Shaul adds that in his assessment even the Bnei Ashkenaz should agree to hold of observing only one day of Yom Tov after living in Eretz Yisrael for a year, or maximum two, but concludes that ‘ain minhagam kein’.
Disclaimer: This is not a comprehensive guide, rather a brief summary to raise awareness of the issues. In any real case one should ask a competent Halachic authority.
L'iluy Nishmas the Rosh HaYeshiva - Rav Chonoh Menachem Mendel ben R' Yechezkel Shraga, Rav Yaakov Yeshaya ben R' Boruch Yehuda, and l'zchus for Shira Yaffa bas Rochel Miriam and her children for a yeshua teikef u'miyad!