Kids need about 10-11 hours of sleep a day between the ages of 7 and 12. Social, school, and family activities will keep pushing their bedtimes later and later, with most 12-years-olds going to bed at about 9 p.m. Some start as early as 7:30 p.m. and others don’t hit the sack until 10 p.m. At these ages, the kids average only about 9 hours of daily sleep.