How long should it take for someone to determine if they want to hire you?

My hire decisions have all come within two days to a week after the interview.

Well, one job interview I did, it took the boss until the end of the interview to hire me. Her 1st words (after saying hello) were "You seem a bit overqualified for this position." So, based on that, at least give the person til the end of the interview to decide whether or not they are a fit or not.......unless they come in wearing their underwear OUTSIDE of their clothes.