Completed 2 system furnace repair and preventative maintenance check. Found both units to be very old and dirty. Recommended ductwork cleaning along with a blower and evaporator coil cleanings. Recommended combustion calibrations for both units. Recommended that the gas lines being brought up to code. Recommended blowing more insulation in the attic to be brought up to code. The customer declined all repairs. The systems are running at this time.