Because I have pretty sensitive flu symptoms that are pretty bad, I really have to look after the air filter changing of my central heating plus air conditioning system extra special more than the usual. I need to make sure that air filter of my central heating plus air conditioning system is changed at least once per month. Because if I do not do this it will happen that the air quality in my property will just start to deteriorate enough to where it will start setting off my flu symptoms. So if I happen to by option forget to change the air filter of my central heating plus air conditioning system once a month, I will be reminded when I start sneezing plus coughing all over the place. That is usually my easy however extreme reminder that I forgot to change the air filter of my central heating plus air conditioning system one month plus then I will go over plus change the air filter to my central heating plus air conditioning system device at that point. But most of the time I absolutely do remember to change the air filter to my central heating plus air conditioning system for that fact alone. So it usually is never a concern or an issue. I always am on top of it plus I feel I will always stay on top of it until the day where I can afford a whole property air cleaner. And then at that point the whole property air cleaner will take care of every single thing in the air quality plus flu symptom section of my home!