Why?
Scrapman,
My experience with Coleman fuel over the years is similar to the other posters here. It lasts 'almost' indefinitely if you don't break the seal. Same deal with the cheaper, generic camping fuel. We have a couple of old cans which are still good and even survived the Katrina flood.
But the bigger question is why would you want to use it? If you get kerosene lanterns, you can burn kero, diesel and several other fuels which are safer and have even greater shelf life. Same deal with various other kerosene appliances.
We have Petromax and Coleman kerosene mantle lanterns, Dietz wick lanterns, Petromax and Butterfly kerosene stoves and a couple of kero heaters. You can't (safely) burn gasoline in the other kero appliances, though you can in the Petromax and Coleman mantle lanterns (though we never do).
As fuel becomes scarcer and more expensive, everyone should try to incorporate as many multi-fuel items into their preps as possible.
Generally, gas appliances only run on gas. You often get a much broader range of use from kerosene appliances.
Coleman fuel is a great barter item and you can dump a gallon or so into a gasoline vehicle in an emergency, but otherwise heavier oils are the better prep course.
Best regards
Doc