There are air and water filters and purifiers that are not expensive when it comes to maintenance, not only that it is also energy efficient and very easy to run.
Most of the time expensive filter replacement only happens when the chamber become clogged by the dirt. Presently, the model of the filters/purifiers has a washable plate so that if the chamber has been clogged it will be very easy to remove. No need to buy and change new filters.
--- permission must be obtained from author Edward Parry to re-publish ---