The Torah commands us to show respect (kavod) to our parents[1] and to treat them with awe (mora).[2] The gemara[3] mentions not standing or sitting in their places as examples of mora.
The main question we will focus on is what is considered “their place.” Rashi explains that standing refers to a communal place where some men congregate for people who seek their advice. He does not explain what the place of sitting is. The Ramah, cited by the Tur,[4] says that one should not sit in his parent’s seat (literally, place of lounging) at home. The Tur implies that Rashi, in contrast, felt that a seat at home lacks the importance for the prohibition to apply. However, the Beit Yosef[5] posits that Rashi agrees with the Ramah that sitting in a parent’s seat at home is obviously forbidden. The Beit Yosef explains that Rashi needed to clarify only where standing would be problematic, as such a formal place does not exist at home.
In any case, the Shulchan Aruch[6] forbids sitting in a parent’s spot at home. The Beit Yosef[7] and Shach[8] say that one may stand where his parents usually sit. This is not the same as taking his or her place in a manner that equates the child’s importance to that of his parents. A contemporary posek[9] asserts that it is also forbidden to sit in a parent’s personal chair if it is unique (special upholstery, armrest, etc.), even if it is not in its usual location. Rav Elyashiv is quoted[10] as saying that the prohibition does not apply to a parent’s bed, which is not a place of honor.
Most sources seem to indicate that the prohibition applies even if the parent is not present. However, there is a minority opinion that if the parent is not present, it is permitted for the child to sit in his parent’s seat except in the presence of a group of people who have assembled around the table.[11] Most poskim permit sitting in the parent’s seat after his death.[12] In many ways, it is a blessing for the parent that his child fills the resulting void and continues his legacy.
A parent can waive his right to honor.[13] Therefore, if a parent permits, his child can sit in his place. Although there is a machloket whether a parent may even allow himself to be disgraced by his child,[14] it seems clear that sitting in another’s place, including a parent’s, is rarely a disgrace.[15] In fact, in various situations, the parent’s permission may be assumed. For example, the Aruch HaShulchan[16] uses such an assumption to justify the standard practice that boys sit in their father’s seat in shul when the latter is not present.
In general, it seems from the poskim that a practical, logical approach is called for. We therefore would suggest the following. It seems that in some families, there is a true parent’s “seat of honor” only at a Shabbat meal, whereas in other situations, places are not designated or taken seriously. Certainly, there is no need to create such a seat, and if a parent moves around frequently for any reason, we would not elevate the seat he sits in most often to the status of his seat. In a similar vein, the Aruch HaShulchan[17] says that while the halacha of not sitting in a parent’s seat applies to a mother, since it was less common in his time for a mother to have a designated seat, the rule often did not apply.
Undoubtedly, the stakes are lower for a guest, as the serious commandment of honoring a parent is not relevant to him. However, it is worthwhile for a guest to ascertain whether there are defined places for the heads of the family. If there are, it would be appropriate for him to respect them as well.