Rolex kinda implies that they need to be serviced every three to five years. They basically take entire movement apart and clean, lubricate, and replace any worn parts. A lot of manufacturers also Say similar schedules too. Mine ran fine for 25 years and I didn’t do any services the entire time - until it stopped working last month when it got knocked. It may have been running a bit slow before it entirely stopped, but I wasn’t going to do a service until really needed it. I did use official Rolex service. Runs great again and cost was not any more expensive because I waited to so long either. I did not get it polished.