Is it time for a sevice?

[Boopie]

My husband bought a nearly pristine 16710 GMT two years ago, from a reputable dealer. It is circa 2002, and I suspect it was worn very little by the original owner. It keeps absolutely perfect time but there is maybe 16 hours of a power reserve. The watch doesn't stop when he takes of off at night, but if it is off his wrist for a night plus almost a full day it stops.

Is it time for service, or would he be damaging the watch somehow if he wore it for another year or two like this? He does wear it every day, and winds it, and takes it off every night for bed. Sometimes he is involved in a home improvement project or some other task where he takes it off to avoid damaging it. This is a fairly new phenomenon, and it certainly wasn't like this when he bought it.

Thanks.