Living somewhere where they salt the roads on a regular basis, I can't run anything other than stainless which really limits my options. I don't want to have to replace my exhaust system every two years....
Same thing if you live somewhere extremely humid and by the ocean, a good part of California. In the northern parts the redwood forests are literally considered rainforests and its one of the foggiest/dampest areas in the world. Toss in a salty ocean breeze and its like living on an island as far as your car is concerned.