The best thing I ever did was buy an e-paper display watch (pebble) which lasts weeks not hours.

the best thing I ever did was get rid of my collection of 41 watches and stop wearing one. my phone already has the time. I don't need a watch

Watches are fashion, for most people, rather than a necessity.

That said there are definitely days when I wander out of the house with a watch and no phone. Fewer these days as I use an app on my phone to pay for bus/tram/train fares, but its still nice to be able to do things without the need for a phone.