Some recent exchanges and observations suggest to me that users not only have different thresholds for voting to close a question yet still applying the same criteria, but that they even apply so widely different criteria that some decisions feel completely incomprehensible to others.
While there always were disagreements about which questions should be voted to close I feel that over time the disconnect became bigger; while there are less visible conflicts (by way of meta discussions) those discussions also had the (positive) side-effect of sometimes clarifying what the reason to close even was.
The idea of this post is to collect some descriptions on what makes one vote to close a question. To avoid this question becoming overly broad I would like to restrict to the closing of specific mathematical question. A lot can be and was said about the suitability of career advice, big lists, big picture, intuition etc. questions; this is however orthogonal to my current aim, I am mainly interest in criteria for the "typical" question.
The principal idea is to collect first-hand descriptions, like:
I vote to close a question when [...]
However, more general statements like: "I think it is reasonable to vote to close a question when [...] yet rather not when [...]" are also welcome.
The purpose of this get some common understanding of the criteria that are applied in practice in the evaluation of questions. This might not only inform future discussions on votes to close but could also help prospective askers to avoid some pitfalls.
The focus above is on votes to close as those come up most frequently and were the subject of the referenced discussions. However, votes to reopen could also be discussed, as well as the review actions "leave open" and "leave closed."