I've had horrible sleep my entire life, teens to adulthood. Started taking magnesium citrate supplements at night, using earplugs, and keeping a 100% hard wake-up time at 6:15 am. It's changed things drastically for me - I don't have to have a solid "bed time", I just go to bed when tired (usually 11pm). I fall asleep in 15 minutes compared to an hour. As long as I stick to waking up at 6:15am, I'm golden.

Learned this by doing CBT-I, where the therapist would start me off by forcing me to get 4 - 5 hours or less of sleep, and record how long it took me to fall asleep. Then I'd gradually go to bed earlier and earlier until I hit an 'optimal' point.