Re-Mask itself can last for a very long time if you care it properly. After every usage, you should hand wash it separately and air dry. Avoid machine washing and drying.
Re-Mask Shield Filter can last 1 week on regular urban usage, however, if you are going to medical areas that might have high risks patients, they recommend you to change more frequently.
DO NOT CLEAN THE FILTER. Please dispose of it if it gets wet.