During my life I have been night owl and an early bird, and everything in between. I've used to go to sleep at the time that during the other part of my life I used to wake up. It's funny how things change.
The only time I haven't been sleeping (regularly) are the late afternoons. That's the time for the naps.
Until recently my rhythm has been progressing towards the early bird. Until recently I used to regularly wake up at six the latest. It was also easy to fall asleep around 10 in the evening. I usually was pretty tired already at that time.
Recently my internal clock seems to have turned back. There is no use going to bed before ten as I would just be rolling there, frustrated and unable to sleep. Maybe if I could fall asleep earlier I could still wake up at six. But if I don't set an alarm I usually find myself waking up around eight.
Of course there is nothing wrong with that. As long as I get enough sleep every night it doesn't matter what time I get it. I don't either have too many early mornings when I need to be up at a certain time. At least for now. Until my rhythm moves even further and I find myself sleeping from the wee hours until noon.