I don't know how long tinned food will keep for. It depends on whether the pantry/cellar is cool, dry, damp etc.
As a child I was taught never to open a tin that was out of shape. If we had opened a buckled tin, never, ever to taste the contents, but to throw them in the bin, as they could cause food poisoning.
I would hesitate to use out of date meat or fish, but I don't know whether vegetables are safer or not.