[hotpotamus]

Citizen has a movement where they throw all the tech they have at it to guarantee 1 second per year accuracy. I remember things like quartz crystals have aging effects, so they used pre-aged crystals - little details like that. It even has an anti backlash mechanism on the second hand so that it ticks perfectly with no visible wobble. It probably doesn't make sense when it would be much cheaper to just use an external radio/GPS time source, but as a watch company, it makes a statement about their craft.

There are other high-accuracy watches (it's mostly a Japanese market thing), and I believe +/- 10 seconds a year is considered fairly pedestrian in that world.