In my car the quart jar is enough for 800-1000 miles. My neighbor drives at least 6-8 weeks before she needs to fill out more water. In the "multi-cell" arrangements there is less maintenance. I have driven with it 4 whole months and only 20 or 25 percent of the water got used up. I washed it all out and put fresh water and everything, but I could have probably driven 6-8 months WITHOUT EVER TOUCHING the system. This starts to look more like standard automotive maintenance, doesn't it?