Water Expert Andy Ball: Changing Resins

With the proper pretreatment and maintenance, the average water softener will not need its resins replaced in its lifetime (20 + years). It is impossible to accurately determine the life of resin since so many factors contribute to the degradation of the resin itself.
Note: Proper pretreatment can be a simple as a sediment filter or as complex as chemical injection system combined with a multimedia bed, this is determined by having your water tested.