Years ago, when I had a busy day and came home, had dinner and then relaxed, I'd feel tired and would usually go to bed and sleep well.
These days, I wake up feeling that kind of tired. It feels like my range of tired has shrunk. Where I used to go from 0 (asleep) to 10 (fully awake and alert) I now seem to never get beyond maybe a 5? I never fully wake up, never feel fully recovered. Sleep doesn't seem to do what it did before -- refresh me. I never feel fully refreshed. Most times I don't feel any type of 'refreshed' at all. I might feel a little less sleepy.
I didn't sleep well as a child and as a teenager, but somewhere between my 20th and 25th (roughly) things changed. I used to lie awake for about 1.5 to 2 hours before falling asleep and then wake up at least 3 times during the night, but whenever I got to decide my sleeping-times I did feel rested. I did feel refreshed. At some point I started falling asleep faster. At some point I needed sleep during the day.
Before, I needed sleep during the day only when I hadn't slept well (or rather, enough hours) during the night. At some point, I started doing brief 'naps' at work, in the bathroom. Not every day, maybe weekly. I don't remember exactly when, but since I still had a job I guess that started about 10 - 12 years ago. I'd feel so exhausted and out of it and unable to concentrate and focus that I'd lock myself up for about 20 minutes just to sit there with my eyes closed.
I thought everybody did that, but it turns out, they don't...