Filter change intervals are subject to mask use, environment and exposure.
If you only use the mask every few days or periodically through the week for simple outings such as shopping or running errands, the filters could last weeks.
If you use the mask every day, we suggest changing every day. If airborne contaminant exposure is low, putting the filters into a daily cycle with a different set for each day of the week is also an option. When not in use, they are placed in a paper bag or container then placed in cool dark place.
If the mask is used in a dusty or an environment with high exposure, we recommend the filters be discard and replaced as needed.
If experiencing a noticeable drop in performance, replace the filters.