[ahknight]

I love that there's not only the internals of a standard three-hand, but the automatic mechanism as well. If you're going pure mechanical, an automatic is the best way. As long as you actually move during the day the watch generally stays wound up (though a twist when you put it on is a good measure). There's a ton of great watches out there powered only by walking around, and it's fascinating to look at what they can do with that.

The mechanics of a six-hand are similar, using the mechanism that is described here for the date indicator.

Another fun device, though more from an EE POV, are the solar+radio/GPS versions of the same. Automatics can hold power for a few days and need walking around to wind. Solar needs light (any light, though sunlight is always best) and hold power for over a month. Many higher-end models can self-set over radio time or GPS signals as well.

When the world goes tits-up someday, both classes of watches will suddenly become essential, and are already essential for people who spend a good amount of time "unreachable" for work or pleasure.

[maratc]

Casio Oceanus S100 is made of titanium, adjusts itself over the radio[0], understands 29th of February, sets itself on/off DST, never needs tinkering or battery change, and sells for a whooping $350. It's the watch you can set all your other watches to.

[0] Don't have radio coverage where you live? "There's an app for that" -- or several -- that simulate radio control signals.

[GordonS]

Ooh, that is a nice quartz watch! Really good review here: https://www.peterferenczi.com/blog/2023/3/19/the-casio-ocean...

[ahknight]

That was on my short list, but I liked the look of the Seiko SBTM339 more (though it's a JDP model so I had to import it). Citizen has a model in that range as well. Then the Seiko Astron line has both radio time and GPS models if you're willing to pay 5x as much (they do look so much nicer, though).

And I can confirm the radio time app works. (For those curious, it plays the time signal over the speaker and the faint EM from the speaker is more powerful locally than the original radio signal at distance, as well as landing on the correct frequencies.)

[matheusmoreira]

Sensor Watch has a temperature sensor and compensation software. It's a Casio F-91W replacement and right up there with the best temperature compensated quartz watches. Less than $100, open source software and hardware.