Most cables usually get better over time. I have seen maybe the bare wire ends of a cable turn a little dark, but under the cable skin the cable was fine. I have never seen terminated cables deteriorate and I have an old M1000 Monster interconnect that is perhaps 15 years old and it's fine. Copper turns greenish and silver tarnishes, but only iron rusts, don't know of any audio cables made of iron.
Buying used old cables
Is there a life-expectancy of old cables? Old cables
can oxidize (rust) and get brittle. Thus, lose their
conductivity. I have old Monster speaker cable in my
storage area which shows darkened, discolored wire. Is
it still useful? Mobility, relocating, moving, bending,
manipulating, as well as aging must have negative
consequences on any cable. Should we consider this in
our purchase of "used" cable thinking we are getting a
good deal?
can oxidize (rust) and get brittle. Thus, lose their
conductivity. I have old Monster speaker cable in my
storage area which shows darkened, discolored wire. Is
it still useful? Mobility, relocating, moving, bending,
manipulating, as well as aging must have negative
consequences on any cable. Should we consider this in
our purchase of "used" cable thinking we are getting a
good deal?