$100.00 every year!Are you the original owner? Apeks has the parts for life program as long as you keep up with the inspections and rebuilds. I just had a yearly service done on my double setup (2 first and 2 second stages) for $100 but I am in the parts for life thing.
I really do not convince that Apeks regs require complete overhaul every yr. 2 - 3 is more reasonable as far as I am concerned.
Rinse it thoroughly after a day of diving especially for the 2nd stage. As long as you don't get any sea water into the dry sealed 1st stage, the only thing you need to pay attention is the IP. Check it before and after a diving trip.