At what point do you worry about accuracy?

[Gab27]

I expect it to perform as-advertised or close to as-advertised, with the understanding that there can be some deviation in performance based on individual usage conditions. In the case of Rolex, their testing methodology for +2/-2 is designed to simulate real world wear, and so I think it is reasonable to expect the watch to perform somewhere close to this, or at least within COSC tolerance specs. My watch does this and has done it for the last 2.5 years of daily wear and so I am quite happy with it.

I don't think it is unreasonable to expect something to come relatively close to meeting its advertised specifications.