Checked all operations in the cooling and heating modes, and inspected both furnace filters. Filters were dirty and replaced with customer supplied filters. Checked all electrical components at the furnace and completed a combustion analysis of the unit. The blower wheels of both units had accumulated a layer of dust on them. Checked all electrical and refrigerant components at the outdoor unit. The capacitor on the left unit was beginning to fail. Both condensers were clean at this time. Customer is holding off on cleaning the blower wheels and replacing the capacitor. Customer is also giving thought to joining the maintenance plan so when the time comes to make repairs he will have the discount. View visual findings from this job here - https://visionshare.xoi.io/?id=XA-0D78-5E2697EBE8FB443C8B3C72B968B3D313