I have noticed a number of attempts to close questions within hours if not minutes of their having been asked. This seems premature to me. I tried to search this meta site for "premature closings" without any result.
Are there guidelines as to how long the OP should get the benefit of the doubt before we throw the book at her?
If a question is offensive speedy closing (and deletion) are of course appropriate, similarly in the case of a duplicate, but I have noticed many cases of questions that don't fall into these categories.
It was mentioned in one of the comments that an other problematic group of questions is "suspected homework". This could also benefit from more explicit guidelines.
A recent example is discussed below in the comments. Another recent example: Tracy tried once, was in my opinion prematurely closed, but showed some determination and didn't give up, and got 2 useful answers. What should have happened?
Note: a relevant link http://meta.math.stackexchange.com/questions/13016/too-quick-to-close