How often should I replace my filter cartridge?

With a family of four, the 10 Stage Water Filter would on average last for 1 year, after approximately 1500 gallons of usage. This includes drinking, cooking, and cleaning vegetables.

If there are only 1 or 2 users, the filter would be good as long as it tastes and smells fine and could possibly last up to 18 months. However, the filter should not be used any longer than this.