Is there a guideline for how long speaker cables will last? I was adding a component recently and got a close-up look at my speaker cables that are about 20-25 years old. They're 12 gauge with a clear jacket so I could see the strands and they appeared to have lost their bright copper color and appeared a dull brown shade. There wasn't any green corrosion color but I'm curious if there is an age limit. Thanks.
