Early Signs of wearing off at the screw Thread
Don't’ make your watch with an aftermarket dial or bezel as it will not be accepted for RVC for servicing even though you have the original proper warranty card.
A proper Rolex Service Slip is in fact the warranty identify on authentication as Rolex will not service any Fake or Frankenwatch.
Send your watch for simple watch repair such as change of Crystal or cleaning say.. they will replace for you the crystal and check the time after cleaning, this is likely minimum service charge you have to pay for your Rolex which you bought from used hand market for Rolex Authentication.
Don't blame your new Rolex for not running as in the manual, you have to manual winding up for minimum 20 times when the watch is about to be used for the first time, or to be used after left for weeks.
Rolex Warranty does not cover casing, bracelet, Crystal scratches and damages.
Don't send your watch to Rolex Service Centre with post-dated Warranty card.
The Warranty will be immediately provoked and the Rolex Shop dealership will be questioned by Rolex.
Proper Way to tighten up your crown is to press the crown again the watch and rotate it anticlockwise a bit before you rotate it Clockwise to tighten up. It will reduce the wearing of the screw threads of both the tube and the crown.
Remember to tighten up the crown when you go for Swimming or diving or your Deep Sea is in Deep Shit!