Submariner - Engine Oil Change

[MagedMS]

Well I've been using a SS Submariner for almost 14 yrs. on a daily basis. I really trust this Sub. It's a work horse.. It never stopped.
A couple of weeks ago I felt its movement getting a bit heavier while adjusting the time and it didn't start working.. So I sent it to Rolex maintenance, the guy there told me it needs cleaning, oil & O-rings change. OK no problem..I sent it (Cost $ 120) and now it's running perfectly..

Since I am an Engineer but not a watch expert, I didn't have enough time to ask the Rolex guy, so can anybody inform me:

-Which parts should be oiled ?
-What kind of oil(s) is used ?
-How frequent a Sub must be oiled ?
-What damage may happen to the engine if not oiled for a long time ?
-How many O-rings must be changed ?
-What is the material of the O-rings ?

Please I need professional answers only.. Thanks