Right fredk!
It's a nuisance and expensive but I have to keep at least 2 filter sets (that's 2 filter cartridges at $175 each PLUS 2 separators at $49 each Plus new O rings and BU rings) on hand at all times plus a can of oil $225.
I can't go a couple of days without air. It's particularly bad when the compressor breaks down and despite the best preventative maintenance that will happen. The pressures and heat generated are incredible and occasionally something inside just gives up. Recently without warning the third stage exhaust valve simply blew out of the head. We replaced the entire head ($700) and then though it would be good to check the 4th stage because that would be the likely source of a third stage problem (don't ask - there is a logical explanation but would take too long to explain here) and discovered it was ready to blow too. The fourth stage head cost $600 so the total bill with labor came to over $1700.
This is in January when most stores are pretty quiet and daily cash flow is lower but, you have no choice.
At $5 a fill (if you can get it), the compressor will never be paid for. The diver air fills don't cover even the regular maintenance costs. The above off-season expense alone will require 340 fills.
Air fills should be $10 to $15 (the cost of 2 bar drinks). At that rate ($15) to recoup the cost of the compressor and the maintenance will require 150 fills a week every week for 5 years.
Hell of an investment Eh!
Spend $35,000 and you'll get back the money you spent in 5 years. That's assuming $15 per fill, 150 per week every week and no unforeseen expenses. No profit!!
Not complaining - just explaining!!