Our current approach towards old questions is now less oriented towards site mechanisms (voting to close, voting to reopen, etc.) and more oriented towards Spring Cleaning. Although the meta post is a little old, the principles remain the same.
If you are looking at an old question (+ answer) that you don't feel is useful for future visitors, we generally lean towards deleting it. Just post a link to the question in the Spring Cleaning chat room and as long as two people agree to delete it, a mod will do the deed.
If you are looking at an old question (+ answer) that you feel is potentially useful, then aim to edit it and improve the tags, language, typography, etc. and we really don't need to close it.
This is particularly so for the homework close reason. I've already highlighted various inconsistencies and double standards in the application of the homework close reason to borderline cases (i.e. not blatant copy-pastes), and I think that trying to apply it to old posts is only going to exacerbate this issue. Because of this inconsistency, I appeal for people to err on the side of leaving open, and I think our stance towards old posts should be no different: leave open, unless it really needs to be closed.
For the other close reasons, it's best to again post in chat and we will mod-close it if we agree. That way we (1) expedite the process (2) avoid dragging old questions through the close vote queue. Of course, if the question is going to hang around the site, an edit to improve the wording etc. would be much appreciated!
If you're on the fence, maybe post in chat and get a second or third opinion.
There are two main actions that lead to a post being bumped to the front page: editing and reopening. Closure is not one of them (and deletion obviously not). We are cognisant of the usual advice to not spam the front page with old posts, but a handful every now and then is perfectly fine. It's not an all-or-none situation where you either edit zero old posts or edit fifty at a time.