In general, most of the cars need to get their air filters changed every year. Replaced filters can have your car to achieve maximum performance of the car and even minimal gas mileage. But in some cases, the interval of time changes between every replacement as some people drive more than others who only drive in the city. Moreover, it also depends upon the condition and environment your car has been driven through. Take an example of driving on dirt roads; this type of place can make your filters get all clogged up soon. But when you only drive on highways at fast speeds, then the filters last longer. To judge your filter, you can check it every month. It can be an ideal and perfect idea if you clean or replace your air filter whenever you drive for an oil change.