[bslalwn]

Quartz can’t either :)

[jsheard]

I guess it depends on your definition of "long period" but high end Quartz movements can achieve ±1 second per year by using a high frequency, thermally compensated oscillator. Movements with atomic radio control can do even better than that of course, though that's arguably cheating since the heavy lifting happens in a standards lab somewhere rather than on your wrist.

[defrost]

Is that a year of ideal conditions with little to no movement or acceration in standard temp. and pressure conditions, or a year at sea in a barometric rollercoaster with 60 degrees celsius cycling heating and cooling with 2G+ surges of roll, pitch, and yaw?

The mechanical marine chronometer challenge is a tough one.

[KaiserPro]

Only citizen can achieve that. There are some watches that use external time references to achieve that level of accuracy.

Most are +-5 or 10 seconds a year.

The problem for me is the citizen isn’t that pretty to my eyes.

[jeffbee]

All electronic oscillator watches are ultimately limited in this competition by the fact that their batteries will run out.