You know a funny thing I learned as a rep, how long it will sit on the shelves! The batch number on the bottom of the can has the date code. I don't remember it now but I would turn cans over and look at that date code and see 5, 6, even 10 years old!
If they are sealed well they will last a long time. Of course if some is poured from it, now you have air in the can when you seal it, that can be a problem. How much is in the can makes a BIG difference. If the can is almost full, that is going to last a lot longer than if the can has a little at the bottom and is largely air.