These advanced filters are a very important upgrade on today's vacuum cleaners, as they force air through microscopic screens, capturing even the smallest of particles such as dust mites, pollen, animal dander, and even most bacteria. After 1 year of usage (average homes, more sensitive homes should replace more often the once a year) these microscopic screens become blocked with the particles, which forces your vacuum's motor to work harder and harder to force the air through the filter. The more often you replace these filters, the longer the vacuum will last