There are molecular changes when current runs though a component or cable. There molecules do not immediately change back as soon as you turn something off. If you took a burned-in component or cable, removed it from the system and put it the closet for a couple months, you may find you need to burn it in again.
Burn In = Voodoo?
I have been an obsessive and enthusiastic audiophile for 20 years, I am not averse to tweaking and The Audio Critic infuriates me. However, I must admit I get a little uncomfortable reading so many posts about "burn in". While I understand that amps may need to warm up, speaker components may need to loosen up, the idea of burning in a cable or say, an SACD player just seems ludicrous to me. Unless of course, the party suggesting the burn in is a snake oil equipment peddlar and needs to make sure someone owns and uses your product for a couple of months before they decide it's really no good. At that point, of course, no one could actually remember what it sounded like in the first place and even if you wanted to return it, it would be too late. Am I being too cynical here?