If clients are taking their vehicle to a dealer they most likely change the cabin filter for them and just bill them for the work or job but majority of us they would not know about the cabin filter and that it needs to be replaced periodically.

It is recommended that cabin filter be replaced once a year especially before spring time so it can filter the pollen dust coming through. If you have a pollen allergy and you wonder you sneeze more while you are in the car yeah good luck with that.