Many questions in Stack Overflow (and I'm assuming the other trilogy sites) have their answers accepted really soon, so soon I'd go as far to say too soon. I've seen questions with accepted answer that was not the best, which the asker even admits (see this question). I presume this behaviour is namely from newcomers to the site.
Allowing a question to be open for longer encourages more, and perhaps better, answers; the quality of all the answers in question would be increased as users attempt to get the most upvotes and get their answer accepted.
I'm wondering if showing a reminder to new users when they post the question, or in the FAQ, would help. It's listed as a guideline in the official trilogy FAQ, but I wonder, who ever reads that?