People who are curious about this, it's worth reading about quartz oscillators in watches and in particular, methods of calibrating them: https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compen...

Get a Casio G-Shock. The 800 models can sync with your phone and the time is auto corrected. I bought a GBA-800 from a pawn broker - out of the dozen or so watches in my box it's the one I reach for if I have to know what time it is accurately.

One of my best bang-for-the-buck purchases was a Casio Waveceptor watch with a hybrid clock face.

The watch uses the WWVB signal for nightly syncing. However, living on the East Coast means syncing is very dependent on day-to-day atmospheric propagation. When I visit more inland, it works great.

The watch face is solar powered, so I’ve never had to change the battery.

It has since been retired after 8 years of use for an Apple Watch, but I think fondly of the mighty job it did.

I love my cheap waveceptor which is always, always accurate.

Actually in the process of choosing a casio lineage (waveceptor movement, metal case, sapphire crystal) - do I get titanium or blacked out stainless steel, lol

Absolutely, get a G-Shock. But get one which radiosyncs. Most phones (and PCs), although synced by internet, reliably lag between one and two seconds.

My synced G-Shock is always correct to within better than one tenth of a second, that is, to the limit of observability. Solar powered, too, so it's just an utterly reliable black box. My favourite gadget by far.

Radio syncing isn't available in my country (no local transmitter and too remote to pick up other countries) so phone sync is preferable for me.

> Most phones (and PCs), although synced by internet, reliably lag between one and two seconds.

NTP isn't nearly that inaccurate.

No, of course it isn't. I said most phones (and PCs). Clients often seem to lag that second or two, reason unknown, but I've always assumed due to software bloat, unstrictfulness, and indirection.

I just checked the price for one of the digital G-Shocks.. I could buy a car for that! A used car, at least. So no, I'll stick with the cheap digital Casio I already have, even if it's a couple of minutes wrong today (it's a bother to adjust them all the time). At least I don't have to worry about one thing: Battery. It seems to run forever. I think the battery was supposed to last 7 years, but by now it's been twice that long. The backlight still works as normal too, if I press that button.

My f-91w gained less than a second over several years... While it was sitting on my desk in a giant climate controlled building within a degree of 22C year-round. When I wore it, it deviated quite a bit more, but still far better than the 30s per month quoted. I was very excited with my experiment at first comparing it to a friend's HAQ that he did wear. Then I realized the flaw in my method.

> and the bus is there exactly on time

So that would locate you pretty unambiguously in Switzerland then?

Heh no :-) - because the railway stations here don't have station clocks with second hands, unlike Switzerland.. heck I don't know why they bother with the minute hand.

> At around 1976-1977 I bought one of those fancy new LED wristwatches, where you pressed a button and the time lit up in red.

This was the vibe I got when the first pre-always-on Apple Watches were first introduced with Raise to Wake - where you had to actively do an action to see the time.

> the bus is there exactly on time

What's winter like in Japan? Is it freezing?