Product review (1 stars): ... use (only two of us) and the 6 month recommended interval is based upon "average" family size
I usually change the filter once a year as there is limited use (only two of us) and the 6 month recommended interval is based upon "average" family size. It functioned fine until, at the 9 month mark, something inside the filter ruptured and it flooded the kitchen within less than 30 minutes.  Fortunately, my wife, who had been outside, had just stepped back into the house, pulled the refrigerator out from the wall and shut off the valve.  The damage would have been unimaginable if no one had been home.  Guess you get what you pay for.