I have some air circuits that are controlled by cams that actuate manual air
valves that look like limit switches with roller arms that follow the cam.
Would I be better off with electric limit switches on the cams and use
electric air valves? The cam rotates at 120 rpm. The dwell on the switch
is 45 degrees.

I do have to replace the air switches every 2 years or so.

I will NOT install a PLC or anything more complex.

I have a similar application coming up and will need to use electric relays
to control air valves or air piloted valves to control air valves. Which
is more reliable? I do have really clean, dry air.

Bill's post made me think of this.