Interconnect Break In?

Wire does not "break in". If it did it would have been observed during the first widespread use of wire for communication - the telegraph era of the 1830's.

 What does change over time is the contact resistance of the connectors due to oxidation. A new pair of cables is installed. A change of sound is noted. The new connectors make a cleaner contact with the jacks. Nothing to do with the wire! So periodic cleaning of the contacts is beneficial.

IMHO most components don't break in. Your ears on the other hand do adjust to the new sound. Speakers possibly are the exception to this with mechanical parts moving air. Individual components in electronic audio gear have such tight tolerances they just don't change over short periods of time.

Ozzy - Thank you.

Jason - I agree that cleaning contacts periodically is helpful, so thank you too. I suspect that there are some early changes that happen based on what I hear and then eventual oxidation.

Willy- Yes, ears / brain definitely adjust to the new sound, particularly when a new component brings more detailer or richer sound. It’ll sometimes take me some hours to be able to process all of it. Yet I’ve also heard dramatic differences after 50 or 100 or more hours with power cords, interconnects, speaker cables, cartridges (where once the bass dropped out before returning after playing 20 hours or so later) and equipment sounds that I’ll say that’s part of it too. Thank you.

"Wire does not "break in". If it did it would have been observed during the first widespread use of wire for communication - the telegraph era of the 1830's"

Somehow, I doubt that the telegraph operators would have paid much attention to the amount of PRAT in their dots and dashes.

Just because a certain someone can't hear something, is no reason to assert that nobody else can either.