How long do the speakers last before a service?

I know I will get various answer, but are there any simple rule? I am aiming for the used speakers. Say if I get a 5 years old speakers. How long will it last with me (presumeable the previous owner take care of them well) before it needs a service/repaired/calibration?

I would feel awful if I can use a used 1k speakers for only a year or two and then need to pay for the service again.

Any rule of thumb on this?

ake