We have the 2 filter model which holds approx 2 1/4 gallons I believe. We've had it for close to a year, and based on our consumption, the filters should last 3 years. The water filtration is relatively quick, 3.5GPH, quicker than our PUR pitcher that it replaced. I typically fill it back up before I go to bed. You can fill it up at any time, BUT, you can also cause it to overflow...
The water is absolutely tasteless which is a positive for me. I would buy it again in a heartbeat!