I had had the exact same furnace for quite a long time.
It always worked really well for me despite the fact that I knew that eventually the afternoon would come when it stopped really working.
It was a much older unit and so I wasn’t sure how long it would take, despite the fact that I knew it entirely wouldn’t be that far into the future considering its age, however despite this I still decided to go ahead and went to get any Heating and cooling tune-ups done. The reason is because, well I understand that he did not pull in updates that can be absolutely crucial to the overall health of your heating and A/C system, I just did not have the currency and I did not want to deal with having a heating and cooling serviceman coming out to our home. I had other things and projects busy around the house that I was placing nearly all of my time and attention on and I did not want to have to worry about having to wait for some specialist to come out to our home to perform the heating and A/C tune-ups. I figured the best way to save money would just be not to worry too much about our heating and cooling tune-ups, after all I have been at least two years without having any kind of standard maintenance or service down to our Heating and Air Conditioning plan is still fine. I do guess 1 of the main reasons that I had lasted so long was because not only when I bought it was it 1 of the top of the line Heating as well as Air Conditioning units, but for most areas I was pretty good with standard service and care. More often than not when I had any kind of maintenance and upgrades performed on it, but had decided to slack off for a short while. Unfortunately after a couple of months the heating and A/C plan did break down and I was forced to have a Heating as well as Air Conditioning serviceman come out to take a look and he suggested that I should have it upgraded! So now I am focusing on trying to have our heating and cooling plan fixed.