This is a common question with no easy answer, the following guide will explain Filter life.Carbon or Sediment Filters:These inexpensive filters are designed to remove harmful elements from entering your RO and damaging the expensive filter. These filters should be changed every 1 to 2 months during regular use.DI (Deionization) Filters:The DI Filter is consumed by both the quality of water run through it and the time that it is used for, so there is no exact time that can be given. The easiest way to determine if you need to change your DI Filter is to measure your TDS regularly, once the TDS is over 25ppm then you should change your DI Filter/Resin.The chart below shows average volumes of water and time of use based on the TDS (quality of water). RO (Reverse Osmosis) Filters:The RO Filter is the most expensive part of your system and if maintained properly will last for years in your system.You will know when your RO needs to be replaced as the system will stop flowing as the membranes of the filter fail.Maintaining and winterizing your system are important steps in keeping your RO functioning, please see our System Storage & Maintenance Article for more details.-