The Ultrapress replacement filters are designed for a lifespan of 300 cycles (150 liters). The lifespan decreases when water with a high content of silt, sediments, or tannins is filtered. The pressing time of the cartridge increases towards the end of its lifespan. When the pressing time reaches 25-30 seconds, the cartridge should be replaced. Even though the flow time increases, the cartridge continues to provide protection. It is advisable to replace the cartridge eventually, despite any ecological concerns.