The air filter of an AC is where the dust and airborne particles accumulate. The more the accumulation, the lesser will be the quality of air in the room. Therefore, you should clean the air filters from time to time to maintain a proper level of air quality. If you can, you should do it once or twice a month if you are using the AC regularly. You should ask the service provider how to open and attach the air filter when they come to install the AC. Apart from that, you should opt for annual maintenance service where they clean the air filter thoroughly along with other parts.