On occasion, when I come across a particularly bad question (e.g. homework with no attempt; or requests such as "why doesn't this work", where no schematic or sufficient detail is given), I'll go ahead and immediately vote to close.
I'm beginning to wonder, though, if this is in bad form. Perhaps I should down-vote, paste a standard form comment, and give the OP a day or two to comply.
How do "you" approach these questions? Is there a generally agreed upon (albeit unofficial) grace period?