I bought the charcoal filter to my Miele vacuum cleaners S5510 because that bothered me the constant exhaust smell. Although the filter removes the smell very well at the beginning, but a slight odor is in the course of time determine. This means that even activated carbon filters only have a limited lifespan. Basically everyone has to decide whether he (she) wants to pay the price but significant or not. Frequent changes of the fleece filter is determined also a good alternative.