Deionization (DI) resins typically last 5–10 years, but the frequency of replacement depends on several factors, including the quality and flow of the water supply:

 Deionization (DI) resins typically last 5–10 years, but the frequency of replacement depends on several factors, including the quality and flow of the water supply:

Water quality: Water with high levels of chlorine, chloramines, iron, or debris can cause DI resin to foul prematurely.

Regeneration frequency: Frequent regeneration can cause DI resin to foul.

Mixing resins: Mixing resins together can cause them to foul. 

To determine when to replace DI resin, you can use a water quality monitoring system, such as a digital meter or a water quality light system. You can also contact a water treatment service. 

DI resins are active until their beads are physically and chemically damaged. To maintain their lifespan, DI resins must be handled carefully.