i do agreed

Not many ppl will send in their watches for regular service..
the old sub i had was working for 10 years (last check was +1 sec/day... 1 sec gain a day, never been service for 10 yrs), it stop after my krabi trip (i used it in some water-activities) and the service only cost me around MYR860...
I have to admit that rolex is one of the most reliable watches i have so far and i do have confident not to service it every 5 yrs until it stop one day ;p
Or, if you find your watch start running slow until a limit you can't accept, then it's time to send back too

p/s: i only have such a good experience with rolex, as for other brand, it's really depend :p