Lol- being an old person I was a little confused by the question for a second. I immediately imagined a big school building with one of those sleepy hats holding a teddy bear sulking as the flag pole tells it to go to bed. And I guess it depends on what time you wake up as well as how much sleep you need. For me, 5 hours is the magic number. Anything different and I find it's a struggle to get out of bed.