Maintenance milestones for a SubC

[chamen]

I've searched for "submariner maintenance" and "when to service a submariner" and found that most general advice is summed up as follows:

1. You should ideally plan on servicing a Rolex every 5 years. It can go longer (maybe even WAY longer), but why risk it?
2. Use an RSC, or a qualified alternative (I read Vanessa's posts and was very impressed)
3. Always take the watch in if you see something seriously "wrong" with its performance

All that said, my personality is one that requires that I change the oil in my car regularly, rotate the tires, etc...which makes me wonder if my SubC should have its water resistance checked, and seals checked more than once every 5 years.

Are there period maintenance checks that should be done on a watch leading up to the 5 year service check?