Arrived to do a performance maintenance. Set up for combustion analysis temperature split and static pressure tests. Found that the system is operating without failing static pressure. Verified operation of all mechanical and electronic components of the furnace. Found that the inducer bearings are making excessive noise. This is a sign of age and an impending failure. Checked blower for cleanliness and to see if there is any play in the bearings. Found that the blower wheel is heavily coated in dust debris. Checked systems heat exchanger to ensure proper venting of flue gas. Found that there is a crack beginning to form but has not reached the point of opening or being unsafe yet. Performed an electronic gas leak search. Spoke with homeowner about systems age and condition. With homeowners approval scheduled a blower cleaning for Tuesday morning. Furnace is operational at this time.