For optimal performance, it is recommended to clean filters regularly. Between washings, your filter can be tapped clean to knock any excess dust and other particles into the waste basket. Pre-Motor Foam Filter: Under normal usage, rinse and let air dry completely (for 24 hours) every month. Pre-Motor Felt Filter: Under normal usage rinse and let air dry completely (for 24 hours) every month. Post-Motor HEPA filter: Under normal usage, clean once every 24 months or as needed. Note: Loss of Suction may occur if foam filter is not cleaned every month. Rinse and allow to air dry completely. Tap loose dirt from foam filter as needed in between washing. Foam filter may appear dirty after use - this is normal.