Silver- gold longtime benefits?

During my current research for some cables I read on Slitech's Q + A page that one of the benefits to using silver-gold wires was that they would improve over time. Whereas Copper wires degrade over time. Saying that for example after a year of use, the differences could be larger than before .
As someone who is presently looking to buy a cables for the long term this was obviously a point of interest.
However is this just one of those' in theory' type truths that in the real world is not worth considering or do copper cables however well terminated and insulated really do deteriorate over time bad enough to affect there performance.
Any thoughts to this? Thanks.