I don't think you have to worry about cooking with old stainless steel pans, unless the handles are loosening. Even if it gets pitted, which some of the ones with less of the chromium and/or nickel in them tend to do more, it is not unsafe to cook in. It's more of a cosmetic thing, how some people have to polish their pans after every use, but once in a while I use some Barkeeper's Friend on them - usually when they get that haze on them, like a deposit of calcium, or something, though it's probably something else.