[_ph_]

Almost all quartz watches have a similiar movement, running of a 32kHz crystal. Those give you about 15s/month accuracy, which is an oder of magnitude better than most mechanical watches and that for a very few bucks. More precise quartz watches exists, but they require quite a bit more effort, which of course translates into costs.

Actually one of the earliest quartz watches on the market from Omega used a 2MHz crystal and was very accurate. Personally I own a Seiko with a 200kHz system, which is good for about 20s/year. Then there are the thermo stabilized systems, which are even more accuarate. The problem is, that the frequency of the crystal depends on its temperature which is the main source of time inaccuracy (there are some watch enthusiasts which do get egg breeding cupboards which have constant temperatures up to tenths of degrees, they make for very accurate watches).

Currently, the best movements on the market are accurate to about 5s/year, which is pretty amazing considering the watches are worn on your wrist in varying conditions. With my precise Seiko watch I could even notice a slight change in speed when I moved quite a distance to a different town with slightly different weather. That shows how big a challenge a really accuarate wrist watch is.

Then there are the market concerns. The most basic and cheap quartz are already accurate enough for most non-enthusiasts. Then, after almost being killed by quartz watches in the 80ies, the luxury watch industry managed to establish a mechanical movement as the desirable item. So there are few expensive quartz watches left on the market, which would feature more sophisticated movements with higher accuracy. And finally, there is a range of higher value watches which receives time signals, be it official time signals in several regions or just GPS signals.

Cornered like this in the market, unfortunately not much money went into high-precisions movements. There are still a few on the market from Seiko, Breitling, Omega and Citizen (there might be more, but those come to my mind). And of course there is the Apple Watch, which is rather affordable and just uses NTP to get absolute precise timing.

[klodolph]

To add to this—I’d say that watches are quasi-temperature-controlled. You wear the watch in varying conditions, but most people spend most of their time in controlled environments, and the watch is directly next to your body, which itself is temperature-regulated. This just means that temperature drift may be less of a factor for watches than it might be for, say, a clock on the wall or in a car.

Assuming you wear the watch.

[erosenbe0]

Indeed, another challenge is crystal aging. For example, PCF2129 has an aging offset register. These devices are rated to +-3ppm over the huge range of -30-80C but the register allows for -7 to 8ppm offsets, if necessary.