Is there a policy, written or unwritten, regarding repeat questions?

I did a quick search to see if this question has been asked before, but I didn’t find anything, so if it has, please excuse the irony.

The guidelines only say that a duplicate question may be removed. It does not specifiy in what cases that would happen. Is there a rule? Say I’d like to ask a question I liked that was asked several months ago, because I’m interested in what new users (or people who didn’t catch it the first time around) might say. Is that acceptable? If so, how long must one wait?

Mere mortals Regular non-policy-making users, what are your thoughts on the matter?