I don't get out solo enough to make AM drops cost effective; I'd end up buying new bottles for one trip and have them go bad before the next time I needed them so I use the pills. That means I either end up carrying two liters of water, or skip refilling and risk running out. Is there a health concern using a pill for a pint of water? That way I could carry two pint bottles instead of a quart and refill more easily.

My understanding is that Aqua Mira has a 4 year shelf-life (even opened)...

I've heard that storing AM liquid in the refrigerator extends the shelf life even more, but I don't know how much more.

Sadly, I just discovered the ClO2 pills I was using were out of date, about $70 worth of them. I tried to get AM to commit on storage life under ideal conditions (moderate temperatures and humidity, no package damage, etc.) but they wouldn't budge beyond the package date. The pills still fizzed when put in water. It broke my penny-pinching heart, but I threw them all out.

How long had you had them?

Really? 4 years would be great. I thought I had heard the life was 3 months once opened. That is so short that I never looked hard at the packaging to confirm.

Michael: the expiration date was 12/09, and the company said that is four or five years after the date of manufacture.