[lallysingh]

That's actually a normal amount for any watch. A well-maintained Rolex is +- 5 seconds a day. AFAIK, only the 'atomic' watches or ones sync'd against your cellphone do better.

Also, 20 seconds means <2 min drift between the adjustments you make for daylight savings time.

[fqyzj]

A Rolex is a mechanical watch, which is an inferior technology.

I expect better from a quartz watch.

[CydeWeys]

The F91W is like $20 though. You're expecting too much from something so cheap. If you pay a bit more than that you'll get a better product. The profit margins on a $20 watch are too low to individually calibrate the rate accuracy of each one, which is the bare minimum that you need to compensate for the manufacturing differences on each individual quartz crystal. And then for accuracy beyond that you would need thermo-compensated quartz, though you only see that on models costing in the 4 figures so if you only care about price performance, you'd sooner get a radio/GPS-controlled model.