This filter is so expensive for what it is and with a growing family, the cost is only set to increase. Right now my house is 2 adults and 2 dogs and we’re using at least 2 gallons a day so I have to change the filter about every 3-4 months. We’re not going to be 2 adults for much longer so it’s only fair to say that I’m going to have to change the thing more frequently as my family expands