Product review (5 stars): The perfect solution to dry mouth.
These things are EXPENSIVE.

... BUT they do the job. My water is delicious, and I only have to replace it every few months. You can buy in packages larger than one and save a few dollars. But truly, you should replace you filter. Yes, you can go a little longer than is recommended, but I would say replace it every 6 months at LEAST. I really do notice the difference. My water is already pretty good up here in the mountains, but I prefer this filtered water. In fact, I think this tastes better or similar to Brita filtered water.

I would caution against buying really cheap replacements. I think the fit in the refrigerator is pretty important to avoid cracking plastic or causing leaks. I think if you bought a nice fridge, you should understand the need to put nice replacement parts in it, not unlike a nice car.