An air filter replacement is needed to prevent dirt and debris from entering the engine. If dirt or debris enters the engine it could cause premature engine wear.
The air filter is located in the air filter housing. To replace the filter opened the housing, remove the old air filter, clean the housing and install the new air filter.
Different manufacturers suggest replacing the air filter at different intervals. Some manufacturers suggest replacing the air filter more frequently if you drive in dusty conditions. When replacing the air filter the manufacturer recommendations should be followed.
Whether you drive in dusty or normal conditions, you would be best advised to follow the factory recommended vehicle maintenance schedule for how frequently an air filter replacement is required. This factory recommendation must be adhered by to maintain the validity of your new car warranty and extended auto warranty, if applied. If mechanical breakdown occurs due to the lack of your car's maintenance of the air filter, the warranty would not cover the car repair.