According to Coleman, 5 - 7 years if unopened and stored properly:

http://www.coleman.com/coleman/faq/faqreturn.asp?question=38

"An un-opened container of Coleman® Fuel stored in a dry area with no rapid extreme changes in temperature will remain viable for five to seven years. An opened container stored in the same area will remain viable for up to two years though will be at its best if used within a year.

Coleman® Propane Cylinders can be stored indefinitely in a dry area. The propane fuel inside the cylinder will not break down."

In my experience, these are conservative numbers, especially for the unopened fuel. They are right on about opened fuel being best used within a year, but it will still work long after that - just a little crankier to get to stable burn and a bit stinkier on shut-down.

I'm guessing that the new plastic bottles will NOT keep fuel usable as long as the traditional metal cans - the plastic probably still allows some oxygen exchange thru the plastic walls.

Note the "dry" - I've had unopened cans develop a leak twice after several years storage - cool nights + humid days = rust from condensation. Garages are not ideal storage locations...

The indefinite on propane only applies to factory filled disposable bottles. Bulk propane has water and other crud in it, which is the main reason why the tanks are heavier and have to be inspected/tested every so often. Factory filled bottles are filled with DRY and filtered propane.

FWIW, sealed up kerosene has an extremely long shelf life - probably in excess of 20 years for all practical purposes.

Last note: The fuel consumption figures cited for the 2 burner stove (hardly matters which model) are high if you have liquid water and low if you're melting ice or snow. There is no reason to run a stove 4 hours/day to cook for 1 - 8 folks.

HTH,

Tom