Pcp pump filter

I think that it depends on the filter. I have two Coltri filters in my compressor's output circuit, and they are supposed to be changed every 23 hours.

What are you using?

I have one of the smallish Yong Heng compressors. It comes with a small fiber filter in the output line. I check it regularly take it out and let it dry when it is damp and put a new one in when it gets signs of oil most of the way through it. I have changed the filter three times in the 15 hours the compressor has run. I have the small filter connected to a larger Tuxing fiber filter which I have taken out to dry a couple of times in the ten hours or so it has been installed but has never needed changed. I changed the regulator on the carbon bottle I often fill my guns from last month and when I looked inside it showed no signs moisture got to it. Yes we hate moisture and oil in our guns.

I also have the Yong Heng + small black filter + big gold filter set up

In the small black filter, a fiber filter element is there for absorbing liquid water. The element need be changed if it starts getting a bit wet . To be safe I replace it before it gets wet .There is no wastage as used elements can be put aside and dried out by themselves before they are reused later.

The big gold filter contains13X molecular sieve to absorb as much as possible the remaining water vapor. Colored silica gel is put at the end to indicate whether the molecular sieve need be replaced. 

Deep blue means no need to replace : 



Turning pink, need to replace :