Depends on the pump.
Electric…the average guy I sell air pumps to changes them 3-4 times/year.
Gas. Guys seem to get 1-2 years from them.
Air. Depends on the material…
Poly…probably 5-6 years. But then you can put new manifold and fluid chambers on and keep pumping.
Kynar/PVDF. I just rebuilt a 1/2" Kynar Wilden a few months ago. It was build in 1997.
New diaphragms, new air end. Pump worked great and is out cleaning every day for one of my clients.
