i would find another inspection station to go to next time. this is over kill, as far as i am concerned; because the problem has not been remedied, but just keeps recurring, and costing.
if this has happened twice, i would be really suspect of having caliper pistons that are corroded or gunked up, and they may be adding to your problem.
i would guess (a WAG at that) that it is NOT the calipers that are the problem. i think the slides that the pads slide on to "self adjust" are getting rusty, and jamming the pads so only one side pad can grab the rotor, thus the recurring "rusted rotors", and accompanying excuses for replacement.
if this IS the slide and pads that are rusting and jamming there IS a solution. I have a similar problem on one of my cars (same issue with low use).
the real problem is finding a mechanic who can diagnose the problem, without just saying: new parts, calipers, rotors, and pads! i have interpreted my problem as too little clearance between caliper slides, and brake pads, so rust (from lack of use) binds them up. my solution is to "make" a little room between so they can "rattle" off the rust.
on my car the rear pads ALWAYS jam in the slides, cocking and then work on one side only. i found if i grind a small amount off the inside of the steel pad mounting U it gives a little "wobble room" for the pads to move along the slides, so the pads dont jam anymore. mind you, i DONT remove any metal from the caliper slide frame, but from the new brake pad mounting plate (the steel, not the ceramic!). AND im only talking about a small amount!