I just got the 4000. It puts out more water than I can use actually living alone. The problem with not running it all the time is that the charcol after filter can grow mold if left to sit. This is true with all water filters. This was one of the topics of the book I mentioned.
The water should be consumed right away. I give some to family and when I still have to much I water the plants, make 3% Hydrogen Peroxide and other uses with the water on hand and refresh my supply with fresh distilled.
Waterwise wanted $299 for my model, I paid $187 at CSPRO. He quit selling them, but ordered this sent direct from WaterWise because I also buy Colloidal Silver from him. I have seen comparable prices elsewhere.
The book opened my eyes about water. Especially bottled water. Some of it is only filtered tap water like Cokes "Dasani" and Pepsi's Auquafina.