Arrived on site to perform heating tune up on 2 lennox unit. Client stated no issues. Cycled both unit and are good. Inspected attic and found black flex ducting used on both and are original. Filter for downstairs are dirty and she will order her own. Upstairs was replaced last visit. Blower assembly and whee on downstairs is dirty from years of operation. Upstairs is good. Blower motor up stairs is good. Down stairs has slight oil and is working hard and almost at max from age and operation. Secondary motor control for blower is boarder line hood at this time and can get weak and out of range. Inducer motors are in range. All safety switches are operational. Drain lines is clear upstairs and downstairs is dusty and no safety over flow on lines. Temperature rise is good on both units. Protection has been added up stairs. Downstairs does not and recommend adding to protect units from electrical surge and power outages. Cycled both units and both are operational. Went over all findings