Sleep deprivation seems to be pretty common among working people and I was no exception.
I sleep like a ROCK in retirement. Before ER I would sometimes stay awake, tossing and turning and fussing over work related things. Sometimes I would even have to get up and do something else in order to stop worrying and fussing. Or, I would awaken in the middle of the night thinking that I had forgotten to do something at work, and experience similar fussing and worrying. None of this happens to me any more at all.
My only sleep issues are due to not having an externally imposed time to awaken (and bedtime) and learning that ignoring this just does not work for me. Like a kid, I just do not want to go to bed sometimes and if I stay up later, I sleep later in the morning, and later each morning than the one before. This does not work for me. For some reason I need a regular schedule but did not know that, and my body did not just automatically provide one for me. I guess that is a skill that I need to learn.
I now awaken to the gentle sounds of morning birdsongs, that my new alarm clock will play for me. No more buzzers, though, and instead of bounding out of bed in 3 seconds or so, I allow myself to drift and awaken gradually over 15 - 20 minutes.
I still have an occasional nightmare, but that is about all that can disturb my sleep.