Probably the easiest place to get this information is from Gregg Jacobs. He is one of the original researchers for CBT-I (cognitive behavioral therapy for insomnia) and has a lot of good information on the different needs for sleep. He’s a bit more rigid about it, saying that for most people, 8 hours is too much. The scientific research I’ve seen suggests it’s not quite that black and white, but it is VERY liberating for people who do NOT need 8 hours sleep to stop trying for an ideal that doesn’t suit their needs.

Good luck with it!