In recent years, due to the rise in the prices of apartments, there are choshuvah [prominent] families who clearly stipulate at the outset that they are not prepared to buy an apartment for the new couple. The question is, is this approach correct, or perhaps since this can cause the children to be stuck in the parsha of shidduchim for a long time, perhaps this is a problem?
A number of poskim say: Today there is no obligation to provide an apartment for the children, and the main obligation is to take care of the chasunah, shadchan, hall, catering and some of the initial expenses of the new couple. However, buying an apartment, and providing money to cover rent over an extended period of time after the chasunah is not obligatory.
On the other hand, I heard in the name of R’ Nossan Kopshitz shlita, that if one has the money, he is obligated to buy an apartment comparable to what other people in the same financial situation would do, as nowadays this is how one fulfills the mitzvah of “marrying off his daughter to a man”. Although the prices of apartments have gone up, nonetheless, one is still obligated as in the future they may go up even more. If one is unable to do this, he is onus [exempt due to pressing circumstances], but if he can, he must do it. R’ Nosson adds: This obligation is more for when marrying off a daughter than it is for when marrying off a son.
One time someone came to R’ Chaim Kanievsky zt”l and said that he married off his daughter and promised to give a large amount of money for the shidduch (400,000 shekel). However, after the chasunah it turns out that the bochur wasn’t as good as he thought, he had yiras Shomayim, but his learning wasn’t better than average [and perhaps the shidduch was a mekech tous, bad sale]. R’ Chaim asked him: Does he wear tefillin? The father said: Yes, certainly. R’ Chaim said: If so, he is worth much more! (Minchas Todah, pg. 477).