It really messes up the limit switch.
Growing up, my Grandpa was a heating and cooling serviceman. He lived right down the street from us, and all of us spent a lot of time over at his house. Grandpa was the type of guy who enjoyed talking about his job to us and he liked teaching us about it, but I remember that he would teach us all kinds of little tips and tricks when it came to the heating and cooling at his house. Periodically, he even let me come to work with him. I couldn’t actually do anything to help him, however I felt like I was really out on the job! That was fun as a young boy; One thing I remember is that a few times a year, I would get to help Grandpa swap out his air filters in his HVAC system. My Grandpa told us that a big problem that he always sees whenever he goes out to work on Heating, Cooling, and Ventilation and A/C calls is simply due to a dirty filter. People do not stay on top of exchanging and cleaning their dirty and congested air filters. Then as a result, it causes injury to their gas furnaces. It really messes up the limit switch. On top of that, dirty filters reduce the efficiency of the gas furnace in your home, too. When I was old enough to live in my own place, my grandpa always made sure to tell me that I needed to change my filters once a quarter, no matter what. I think of my Grandpa everytime I change my filters.