Although I agree with Kit for the large part, I think in some instances it isn't immediately obvious that necessary information is missing.
Requests for more information from the community are a good indicator (but not a guarantee) that a question needs more content. Being too quick to close a question could also scare the OP off for good.
I would say that 24 hours is long enough to see if a question needs closing, and it gives the OP a chance to come back and add content during the same time of day that they posted.
Unfortunately most of the time wasting would have been done by then, as it would have had its time on the main page.