I don't have any sources but for a lot of people this seems to decrease with age. I'm 28 and I can still sleep for 10-12 hours if I don't have any reason to get

I don't have any sources but for a lot of people this seems to decrease with age. I'm 28 and I can still sleep for 10-12 hours if I don't have any reason to get up, which is rare. However, I don't think my dad can actually sleep more than 8 hours if he wanted to.