The exchange is easy to accomplish. The construction of the module prevents erroneous insertion. The effect is excellent. Combined with the Miele filter bags no fines and odors get more into the exhaust air flow of the vacuum cleaner. Especially for people with allergies, this is important. A rubberized gasket ensures an "airtight seal" on the exhaust duct.
Whether the filter block has to be replaced after a year is dependent on the frequency of use, amount of dust and humidity.
Of course, the filter is quite expensive but it is advisable not preferable for cost reasons an alternative manufacturer because they are not comparable in quality and effectiveness.