We know that you might not give your furnace a lot of thought. All that matters for you, for most of the winter, is the temperature on the thermostat. Hopefully, you schedule furnace maintenance every year as well, but that won’t stop a furnace from failing.
Eventually, your furnace will need replacement, but you may not be able to tell when that is. Follow our advice on how to figure out you need furnace replacement, but always consult with a professional first.