It's a crapshoot for me. 13 years ago I started waking up at 0323 every morning.....like clockwork.....on a digital clock, for two weeks straight at that exact time. Never did figure that one out. It was really odd and frustrating. But these days it's anywhere between 0230 and once in a blue moon, maybe 0800. I do find that regardless what time I go to bed, I wake up almost exactly 5 hours later. Sometimes I can get back to sleep, sometimes not. Today I got up around 0430.
4:15 -4:30. Every morning for 30 years. I never sleep in. Never miss a sunrise. I like being up early. It makes it easy the many days a year I need be up at that time to hunt or fish. Its just another morning.
I see guys dragging their rears out of bed two to three hours ahead of their normal routine. They aren't on their games and sometimes even are miserable.
On the other side I ain't exactly the life of the party after 8:00 pm.
Every year of age it seems to get about 10 minutes earlier. I'm mid fifties and it's about 5AM with no alarm 7days a week. I'm on pace for 4 AM when I hit 60.
I'm quickly approaching SS FRA and I'm with @NRA4LIFE on this one as I sleep as late as possible.
OTOH, I seldom go to bed before 0100, and often it's 0200, and that's even the case when I have to work the next day when I'm up at 0830 (I know, the inhumanity ).
Been that way my whole life....always hated getting up early even though I've done it 100's of times when it had to be done.