The photocatalytic filter is made of ceramic coated in tungsten trioxide (WO3), it’s ideally designed to last forever, unless in case of breaking during.
The filter is washable under the water, in order to keep it always clean all you have to do is rinse it with water at least once a month. Cleaning frequency may be different from case to case, depending on the indoor space where you have placed your Natede Smart.
The ceramic filter is covered by a 2 years warranty.
For the regular maintenance:
You can watch the following video: