Have had my unit 14 years and have it serviced two times a year. Part of my service is to have the filters replaced by the serviceman. They obviously don't use Filtrete filters. Each time a new serviceman shows up to do the work, they always comments that the unit looks brand new. They know not to replace the filters since we ONLY use Filtrete. Many of our friends and family have told us that Filtrete is expensive but I do believe a new unit is more expensive!! With the rebate program it is quite manageable.