cable break in

A 'good' answer is in the mind of the beholder.

I suspect there's no difference in conductivity after conditioning. What gets conditioned, mostly, is the insulation.
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Jefferybehr is correct. In addition, at least according to the transcript I read of a formum of power cable/interconnect manufacturers, the consensus seems to be that the conductor<>insulation interface goes back to its pre-break-in state after a period (several weeks) of non-use. Also if IC's are reversed in the system, they have to be re-broken-in so that interface can be (molecularly) reoriented. At least that's what I read FWIW.

Nsgarch's additional info is consistent with my understandings.
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