no not every weekend...but last friday night, I went to bed at 11PM, and woke at noon. I dont get enough sleep on school days. 15 hours is an exaggeration...but my record is 20 hours in one night...i pulled an all-nighter the night before, went to bed at 5pm, woke up 3pm the following day...it screwed my sleeping schedule up horribly...I wasnt able to fall asleep for a week or two.
But on school nights, 7-8 hours. On weekends, 12 hours or more, unless ive got to go somehere in the morning.