There’s no one-size-fits-all answer. The frequency of filter changes is driven by how much your HVAC system operates, which is driven by the severity of the seasons. In some locations the cooling system might be in use more than four months of the year – to keep heat and humidity under control. If your house is in such a hot and humid location, you should pay a lot more attention to your filter than in an area where the air conditioning is seldom used. The same logic applies