I've always been a night owl, left to my own I'd stay up until 2am and wake 10am.
That schedule seriously doesn't fit in well professionally (boss likes me to work before 9am) or socially (friends get off work by 5) or exercise-wise (club bike rides 8am weekends, 5:30pm weekdays).
Since age 40 insomnia has been rough trying to fall asleep. Since age 50 I have been taking sleep meds. Now it takes me an hour to drift off to sleep but after 2 hours I'll wake up and toss and turn for 5 hours. Then around 5:30am regardless of when I went to bed, I'll get my best sleep. I'm rarely tired at bedtime, and most bikerides make me too tired/wired to sleep well.
I have mild epilepsy and going on less than 8 hours sleep sets me up for seizures. I do much better when I drift back to a later schedule and get more quality sleep than I do trying to go to bed early to wake up early.
Decades ago I could get by on 4-5 hours sleep then sleep 12 on weekends. Not now.