I haven't used an alarm clock in at least 15 years. Unless I am getting on an early plane. Then I set three clocks and still wake up every hour. I probably should just stay up.
It's not that I have any real trouble sleeping. But I usually wake up about 5:30 a.m. Then my brain starts to run, and I lay there thinking about things I could be doing, lots of things I'd like to be doing. Sometimes I'll stay there and try to go back to sleep but most of the time I get up. It's my favorite time of the day. If the weather is right, I'll sit on the deck with my coffee and the dogs. Or I'll read.
Even as a teenager I don't remember sleeping late. Lots of nights when I wake up, I'll turn on my light and read for a little while until I feel sleepy again. Those mornings when I let myself go back to sleep and then wake up after 7:00 a.m., my first thought is What a waste of time.