When I still worked I have 4 to 5 hours of Siftenaben, decades. That was enough with completely around my day rested and fit to attack.
Today with 70 I sleep longer, 6 hours about.
completely different, mostly between 2 and 7 hours
I usually go between 23 and 01 Clock to bed, sometimes later. Normally I am at 7, half past 8
General 3h in the night
on work usually no sleep
Most of the time 7 hours