Performed preventative maintenance on AC system for customer. Customer met me at front door and we discussed maintenance needed, any issues, and filters. Customer stated the system is running fine and that he would be taking care of the filters. I started my inspection with the equipment in garage. Inspected the blower assembly, motor, electrical components, evaporator coil, drain and overall condition and operation of equipment. Evaporator coil is rusted, signs of aging. Cleaned condenser coil thoroughly. Inspected condenser coil, compressors, fan motor, capacitors, contactors and overall operation. Checked thermostat operation, amps, temperatures and pressures in both stages of cooling. Second stage of cooling shows system to be running just a tad under charged. Brought this to customers attention. After discussing the matter, customer wanted to leave as is for now. I let him know that the system may run longer in order to sustain temperatures in home when the system isn’t properly c