The answer to 'lifespan of furnace repair' is that with proper maintenance and care, most furnace repairs can extend the lifespan of your furnace by several years. Furnaces typically last 15-20 years, but major repairs like replacing the heat exchanger or blower motor can add 5-10 more years to the furnace's lifespan.
Regular tune-ups and addressing issues early on can help prevent more costly repairs down the line. However, at a certain point, it may be more cost-effective to replace an older furnace rather than continue repairing it.