For a few weeks now, I'm owner of a smart watch again. I used a smart watch some years ago (during the Android Wear 1.0 era), but stopped using it when my watch (the Sony SmartWatch 3) didn't receive updates anymore and was almost useless since all apps where just optimized for the Wear OS.
Now I'm back with a Galaxy Watch. It's a pretty great smart watch. For one, I like that it's using Samsungs Tizen OS instead of Wear OS. Yes, that's true, because Samsung's software asks way less to allow access to all different kinds of data or it's easy to just deny it. Bixby is also less annoying than Google Assistant and I can just hide it on my watch.
Another advantage of this watch over my old smart watch is, that it has a sensor to measure my pulse. Due to that it can also track my sleep. A feature I learned to love.
I wear this watch almost 24/7, so when it isn't charging (that needs to happen every other day), it's on my wrist. Even during the night, so I can check how long and well I slept.
I'm a short sleeper and consider a night with 8 hours of sleep a very good and long night. With just 6 to 7 hours of sleep I'm quite ok, although I sometimes feel tired. One reason I'm probably sleeping less than others do, might be that I'm quite sensitive to light (in the morning) or sounds (when the neighbor's baby cries).
One way that helps me get at least those 6 to 7 hours of sleep instead of just 4 or 5 hours, is to force myself go to bed early. I try to go to sleep at around 10 pm to sleep until 6 am. Often I'm already awake at 5 am though.
My watch helps me with sticking to my bed time. Because I know it will track my sleep and can show me how much I slept the next morning, I can see a pattern of less sleep (also another distribution between deep, light and REM sleep) when I go to bed later. When I go to bed at midnight I get just 5 hours of sleep and feel very tired the next day.
Looking at and analyzing my sleep data (sure, I shouldn't focus on that too much - it can create anxiety when you wake up too early and think about all the lost sleep) is a great reminder, that the earlier I go to bed the better and longer I sleep, and also the more energy I have the next day. It's one case where actually knowing the numbers is the best reminder to behave properly.
It might also help when more people would calculate their ecological footprint, but that's another topic…