[Alistair]

I tried with my Apple Watch for a few weeks. The data it provided didn't add value for me. If I sleep poorly, all it did was confirm as much the next morning.

It failed to differentiate between "asleep" and "awake and lying still so as not to wake my wife". There were nights where I absolutely had periods of lying still and awake that just registered as "light sleep" to Apple.

It did report shockingly little REM sleep, but I'm not sure if that's actually useful. I was otherwise rested when I felt I slept well.

Edit - alcohol definitely impacts my sleep, but I knew that without needing a tracker.