All air purifiers will have a different maintenance time frame which will be suggested by the manufacturer. With this said also understand that it is in the manufacturer's best interest to sell you replacement filters for the life of the machine.

Pre filter maintenance:

Try to check on the Pre-filters intermittently. If you need to change it every 12 months then pull it out every 6 months. Gently use a vacuum cleaner hose on it if there is a lot of dust build-up. This will free up the pores and allow the air to flow freely which will reduce the stress on the fan and motor.

Also by allowing the air to flow easier you will then allow more air to pass through the filter more frequently which is what you want. You want the air to pass through the filter as frequently as possible. If you are pulling the air in through the filter faster than the room can re-pollute itself then you will stay ahead of the contamination process. 

HEPA filter maintenance:

Not all machines have a pre-filter. If your machine does not utilize a pre-filter then the first line of defense may be the HEPA filter or the (High-Efficiency Particle Absorbing) filter. Then without a pre-filter, I would suggest checking the HEPA filter periodically and if needed pass the vacuum hose on it lightly. There may be some large particles like hair or fibers that could potentially clog the machine and restrict airflow. This process could possibly extend the life of the filter beyond the manufacturer’s recommendation buying you an extra month or two until you replace the filter.

Carbon filter maintenance:

There are two popular styles of carbon filters. First is the carbon granule type which is usually made of some type of wood such as coconut shell heated to a high temperature which will form charcoal and is usually enclosed inside a separate filter container or in some cases injected into the middle of the HEPA filter. You can not prolong the life of this type of filter because it is responsible for absorbing odors.

I always suggest changing out this type of carbon filter at the recommendation of the manufacturer. Once the carbon filter is saturated, it will no longer absorb odors and if it is not changed out, it may actually repel odors. Secondly, there is the carbon-style pre-filter. Which is usually a thin dark-colored strip or sheet either wrapped around the HEPA filter or laid directly before it as the air flows inward. It is usually some type of man-made material coated with a layer of carbon but also acts as the pre-filter. So just follow the pre-filter maintenance recommendation from above with this type of carbon pre-filter.

Follow this maintenance recommendation to prolong the life of your machine and get guaranteed results.