One of the longer posts by awap.
WhiteSands: Listen to awap & company and you'll be in good shape. The same attitude toward replacing parts is also reflected in the later parts of Harlow's reg servicing book.
The related question, how frequently should one open up a reg to clean/service, is a more tricky one. Despite what some say, HP seats are not easy to get. In my limited experience, not replacing one has invariably led to IP creep. Following herman's recommendations may be a good approach.
Lastly, the real tricky question (for me) is 1st stages used with deco bottles. Deposits build up which don't affect regulator function but with 100% O2 in the deco cylinder, combustion, in principle, may become more likely. Since we don't hear about tec divers blowing up on a regular basis, my sense is that the danger is exaggerated. However, I'm conservative, so plan on O2 cleaning my two deco regs once a year. And use 50% O2 when the additional off-gasing benefit of 100% is marginal.
