An UltraPress cartridge is rated for ~300 cycles (150 liters / 40 gallons); GeoPress cartridge for ~350 (250 liters / 65 gallons). The effective lifespan of a cartridge varies depending on the quality of the water sources—the clearer, the better. High levels of silt or sediment will shorten the lifespan of a cartridge. To maximize the effective lifespan of your cartridge always choose the clearest water available. If necessary, pre-filter the water using a handkerchief or t-shirt as you fill the Outer Refill.