I’m traveling tomorrow to look at a 2001 Datograph. The seller is a dealer with a great reputation but does not know whether the watch has ever been serviced. How nervous should I be about the possibility that the watch has never been serviced in its 17-year life? I’m assuming I’ll need to send it in for service at some point in the next couple of years, but is doing so an immediate imperative even if the watch seems to be running well?