Had a conversation with a chemist from a pharmaceutical company recently. his report: the expiration dates placed on medications and consumer chemicals are placed there, not by scientists, but by marketing departments. These dates are designed to encourage folks to discard useable products and buy new ones. Loss of effectiveness, chemical decay, loss of sterility, too-is event related, not time related. If drugs, chemicals, are stored in intact packaging in a cool, dry, dark place-that is away from IR and UV light, water and heat-things that cause chemical reactions-the drugs will remain unchanged for a very long time. If the package is not intact, if the drugs are directly exposed to heat or light or water, they will degrade very quickly-doesn't matter what the date on the package says. If sterile water is stored in sterile containers, it will remain sterile until you open the container and put some bacteria in it: event related, not time related. The place where folks seem to worry most about the outdates here is in the chlorine tabs used to disinfect water in the PSK. Simple solution: a plastic dropper bottle filled with clorox or another sodium hypochlorite bleach. 8 drops per gallon and 30 minutes is recommended. (http://www.epa.gov/safewater/faq/emerg.htm). store it in a ziploc bag to foil the inevitable leakage. Worried about it outdating? replace it weekly, it is really cheap. Worried about drinking chlorine? you do it every time you swallow municipal water. Think bottled water is the answer? Most bottled water is made out of local tap water that has been run through a reverse osmosis process (a process of uncertain result and value) and then popped into designer containers. It is tap water. It is processed in a plant that is inspected much less frequently than your local water works, and it is all okay because our tap water is so incredibly safe compared to the stuff that the rest of the world is drinking. And we pay more for a gallon of Evian water than we do for a gallon of gas. oi. next rant: dumb stuff in FAK.