how long do you usually wait before giving best answer?

Tough question.

I would say it depends on the category. Singles and Dating is a different kettle of fish than Physics, Chemistry or Math. In the sciences, you have to follow the steps of the answer given. If it seems reasonable, award the BA.

In the category you've posted this question, I would wait a couple of hours until all the answers appear to be in and then choose one. That could take a bit of time.

I have asked 28 questions. My feeling is that it’s a good idea to have a minimum of 4-5 answers before I award best answer. I consider the number of good responses rather than the amount of time to wait to award best answer. Of course, it can take a few hours before you get a bunch of good responses. Sometimes you may only get one answer, so you may end up awarding best answer to that response if it’s decent. From what I’ve seen on the board, many questions are asked, so questions go down the board very quickly, which can make it hard to get a bunch of answers. Also, if you don’t really like any of the responses, don’t feel that you must award best answer. Some people provide stupid answers, don’t really answer your question, or troll.

I have yet to ask a question.

I've answered over 20,000.

I'm at a loss.