Answer: The frequency of change may vary depending on the water quality, the amount of water passing through the filter, and the specific requirements of the application. For a carbon filter of this size and specification in a typical household or light commercial use, changing every 6 to 12 months is typical. However, this can change depending on the amount of water being passed through and the load of contaminants. It is important to keep an eye on the performance of the filter and change it if there are signs of reduced efficiency, such as changes in taste or odor in the water.