As you know the messenger particle for all electromagnetic forces is the virtual photon. My extensive research into this question had led me to the discovery of an effect which I call "Photon Fatigue" in which the wires simply get tired of letting the little buggers slide down them. But fear not , I am on the edge of a breakthrough which will completely eliminate this problem and make me a lot of money from people who worry about such questions; I will put you on my mailing list.
Do speaker wires degrade over time ?
I am looking buying a pair of used speaker cables from the 80's. I have no idea if there is a life expectancy on cables. They are probably broken in !