I service my dry vac pump myself. truly I do.
in 10 years it hasn't shown any wear at all.
I did get a guilty feeling once about servicing my vac pump and making a few new parts in it so I bought an unmodified yellow tagged one and put it on the aircraft.
it failed in exactly the same way as the first one. so I made the necessary replacement parts for that one as well. while I was doing this I put the original one back into service.
I love dry vac pumps. they are a nifty little device. with my periodic servicing my two dry vac pumps will most assuredly do me for the rest of my life.
....I know, not what you wanted to hear
