ANDY'S ANSWER: Teenagers need a minimum of 8 hours of sleep per night in order to to function at their best. If your teen has to get up on school days at 7 am, I would say that lights out should be no later than 10:30 pm, to give them time to wind down and get to sleep. It's probably even best to be in bed at 10 pm and read or listen to music for a half hour. My parents always gave me a bedtime that was the time I had to have my teeth brushed, pajamas on, and actually be in bed.