Performed furnace maintenance on ComfortMaker unit. Met with wife, husband was not home. On arrival wife did mention that she has work meetings, and would like for me to call her husband to go over any concerns or the maintenance. Cycled system for heating. Verified proper heating sequence of operations. Ran system through 20 point inspection checklist. System does have a number of concerns. Called husband and went through information over the phone. He is fully aware of all condition and concerns of the unit. He is still unsure if they will be living in this home for long enough to decide to replace the unit. Wants to hold off on any work for today. Replaced filters provided by customer. Cycled system, system is operational upon departure.