Coleman says that an unopened can, properly stored, should be good for five to seven years, and fuel in an opened can will remain good for two years, but should be used within one. That said, I have had the same luck with the stuff. I once dug out my ex-father-in-laws old Coleman three burner stove, which I know for a fact had not been used for over 20 years and still had fuel in it. Fired right up, ran 'til dry, and I used that stove for about ten years without a problem. Same thing with my dad's old single mantle lantern. Didn't have to change generators or anything on either of them. That stuff doesn't seem to die, no matter what Coleman says...