From like 17-30, when I was getting fucked up on the regular, I didn't seem to need much sleep. I'm sure a lot of it had to do with my body, brain, and nervous system being in some sort of shock. there was a period where I was working as a teacher and I'd stay up rampaging all night, sleep for maybe 2 hours, get to work and hold down a classroom. My supervisors, colleagues, and students were always stoked on my performance. I really don't know how it went down like that. I guess I was just used to operating without much rest.
Nowadays, I like to get about 8 hours. I don't have to use an alarm, I pretty much wake up between 630-730 regardless of when I fall asleep, so I try to get shut eye between 1030-1100. It really helps on days when I've been super active- build a project in the yard, skated, went running, long bike ride, etc. I'm also totally into herbal sleep aides- kava tea, Passion flower, magnesium, Valerian. I take this stuff called formula 303, it's passia flora, magnesium, and valerian in a tablet. It's quite relaxing and the magnesium is a great muscle relaxant.