The manufacturer recommends changing the Sediment and Carbon filters every 12 months, however depending on water quality they may need to be changed more often. The Membrane should be changed every 2 to 3 years.
Having slower than normal water production is normally caused by two things, the first would be the filters have clogged, the second would be the membrane has clogged. If the membrane has been changed within the last year we would recommend changing the filters first and seeing if that fixes the issue. Then if it doesn't, or it has been 2 years or more since the membrane has been changed, it would be recommended to change it.