I've always understood the idea of "break-in" as it pertains to mechanical-to-electrical, or electrical-to-mechanical interfaces. (Cartridges and speakers.) But I've never "gotten it" with anything else. Capacitors, maybe. I don't get cables either. Assuming, of course, proper gauge and good construction techniques. I've got a great double-blind A/B test box designed, but as I'm not a rich man, I'm not going to spring hundreds or thousands of dollars on a sample cable or two. Unless some manufacturer donates some to me, I'll never know for sure. (And they won't, because I'm not a pro reviewer.)