Chris Hannah just bought an Apple Watch Series 3 and will be using his Series 0 as a dedicated sleep tracker:

I started by removing all the apps, turning off the features like handoff, bedside mode, notification indicators, and activity monitoring.

Then it was the watch face, so they were all deleted, apart from a modular face. Which I have customised to have the time in the top right as usual, and the middle complication is the alarms. Everything else is blank. Because what else would I ever need to see if I’m in bed? Hopefully I’d be sleeping.

There’s also a few more little settings that will make the sleep-watch experience better. For example, the brightness is the lowest it can go, the text size is a bit larger, and it will be on Do Not Disturb, Silent, and Theatre modes, all the time.

So it now does nothing I guess?

Oh except, I installed AutoSleep on it.

I don’t think I could ever part with my Apple Watch Series 0. It’s the timepiece I wore at my wedding and it’s garnered a bit of sentimental value as a result. But this seems like a brilliant way to continue using an older Apple Watch beyond its typical lifespan. When I eventually buy a Series 3, I expect I’ll use it for sleep tracking as well.