Let's say that there is a question asked in a bad manner, in a way that the question is missing. For example the user shows the code and doesn't explain very well which is the problem.
Usually someone starts digging in the OP mind posting comments and asking him for details. It may happen that the question gets edited and the OP edits it to a valid question.
Do you usually give the OP time to edit the question or you immediately vote to close it?
When I sense a good question buried within a vague wording, I for one try to get it closed as soon as possible.
Thing is, vague wording is a road to closure anyway but while open, it can attract irrelevant answers which will make it difficult (as explained here) to further edit the question into the shape allowing to repel garbage answers and reopen it.
As you can see, fast closure here serves the primary need to make reopening easier and protect the poorly worded good question from getting bad answers.
It really depends on the question. If it's a question terrible enough that no amount of editing is going to make it appropriate, I will vote to close immediately. On rare occasions this happens within the first minute of a question being asked.
More often than not however I ask the OP to address the problems I see and I will revisit the question. If after a reasonable amount of time there has been no response (a couple of minutes most often, or sometimes I wait for some user activity), I do vote to close. And I don't hesitate doing so. Voting to close does after all not mean that the question is dead. And it has the added bonus of protecting users from answering a question which might end up being a moving target when edited.
It really depends on the situation. How the "question" was asked, how much effort was put into it (spelling, formatting, etc...).
A big consideration, for me is how "new" the user is to the site. If this is a users first post, I'll usually put off the vote to see how engaged they are with the site and how they respond to comments suggesting how to improve the post.
Of course if it's a users first post, and it is off topic, and the only thing to comment on is the fact that the question is off topic, I'll vote immediately.
If I'm dealing with a user that already has a couple of posts on the site, I'll vote now and ask questions later.
new_user === bad_question. I'm saying that it needs to be taken in to consideration.