How often do the filters have to be replaced? How much are the filters?

There are a lot of factors that can impact how often you might want to replace a filter. How many hours the vac is used per day, the types of dust being collected, etc. As a general rule of thumb, HEPA filters can last several years before requiring replacement. When cleaning a HEPA filter, tap it against a surface. Avoid using compressed air, which can compromise the filter by creating very small holes. HEPA is rated to 0.3 microns for particle capture, so even a microscopic hole can reduce its effectiveness.The part number for the replacement HEPA filter is 49-90-1952, which is currently priced at $79.https://www.toolnut.com/milwaukee-49-90-1952-hepa-filter-for-8960-20-dust-extractor.html