When I first retired, and kept getting asked 'What is the worst and best thing about retirement?', my reply to Best thing, was always - not having to set an alarm clock and letting myself wake naturally.
This was a long time ago, and I do use the alarm most days now.
I had sleep apnoea (undiagnosed) for some years, and was so.....very tired increasingly. Was going to bed about 9 pm, up several times in the night for loo trip, then up about 8 am each morning, but falling asleep in my chair for a further hour after my breakfast.
Once I got my CPAP machine everything changed.......I now go into my bed just before 10 pm, but then spend the next 60 - 90 minutes listening to audio book whilst doing Sudoku puzzles. Settle down then to sleep (put on mask), now only need one loo trip each night (about 4 am ish), and usually go back to sleep pretty quickly. I always set alarm for 7.45 as I like to be out of bed by 8.00 am
Quick shower, then long brekkie (just mug of tea and porridge), but then spend a happy hour on laptop - before getting dressed and going out. Most days I have something to get to by about 10 ish, prefer morning things, and rarely go out in the evening - that is my tv and knitting time.