Performed preventative maintenance on heat pump AC. Customer has taken care of filters. I inspected the blower assembly, motor, electrical components, evaporator coil, drain and overall condition of equipment in attic. Recommended new pan treatment to help keep evaporator pan and drain clean. Customer approved. Replaced the pan treatment and began checking outside portion of equipment. Checked capacitor, contactor, compressor, fan motor and operation. Checked thermostat, amps, temperatures and pressures of condenser. Systems compressor is starting to lag a little when initially running, and then smooths out after about 5-10 minutes of running. Recommended to customer about preparing for replacement soon. System is still operational within manufactured specifications, but is starting to struggle.