Performed ac maintenance x3. Cleaned systems, replaced filters, and checked for proper operation. On the upstairs and basement systems the capacitors were performing below spec and I recommended replacement. I found the main floor system to be low on refrigerant. With customers approval I performed a leak search with an electronic leak detector. I searched service valves, the outdoor system, and the indoor coil. I found damage on the outdoor coil caused my either ice or rocks but did not get any substantial hits here. I also found rust a corrosion throughout the indoor coil but once again did not receive a definitive hit. I spoke with the customer and showed the condition of both of my concerns. I went over estimates of charging the system to spec or charging the system to spec and adding leak sealant. Customer did not want to move forward with either of these at this time. System running upon departure.