Because tap water has considerable amounts of minerals, main ro membrane and resins may last 2 years. Homes need a water softener to remove minerals BEFORE being water filtered by rodi filtration. A must, rarely doneSimple question today - how often do you have to change your DI Resin. Many factors can dictate how quickly you have to change it, so feel free to discuss your situation. Others may have suggestions on how to possibly extend its life.