Yosef Karo

“ If, however, one says "I make the condition that when they fall I will eat them," this is not effective at all. If one says, "I stipulate that I can eat them whenever I want," this is effective as twilight is included. Rem"a: One must make the stipulation before twilight of the first day (his own words based on the opinion of the Orkhot Hayyim brought by the Beit Yosef and not like the Mahari"l) . There are later authorities who write that these days it is not our custom to stipulate (Mahari"l) and this is how we act regarding the decorations hung from the schach. ”

“ We do not benefit from them for other things for all eight days because on the seventh day the sukkah itself is entirely muktzeh until twilight, and since it is muktzeh for twilight it is muktzeh for the whole [eighth] day. Rem"a: Even if the sukkah fell over, it is forbidden, and a condition [that it will be permitted if it falls] is not effective (Tur) . But wood that leans on the sukkah is permitted [to be used] , see 518:8. And if after the minimum requirement for the size of the walls is met and the valid sukkah is complete, one adds a wall, it is not forbidden. ”