I notice that on the 'quotation' thread, the burn in nonsense has raised its head again.
As (I would guess) one of the few on this forum who has designed equipment to be burnt in I wanted to explain what it is, and what it isn't.
Electronic components suffer from high infant mortality rates - either they pack up early, or they last for ages. If you are making equipment where failure is expensive or has consequenses (aerospace, medical etc), then you want to weed out the equipment that is going to fail early. Running the equipment at elevated temperature accelerates the failure (many failure modes are heat / thermal stress related). If your box survives burn in, then its probably going to last for at least its designed lifetime. This is burn in.
What burn in is not, is some miraculous process whereby components somehow drift into spec over a period of usage. Amplifiers are not like Ford Mondeo gearboxes, they dont need to rub the parts together for 3 months for them to work properly. The following link is to Radiospares, a company that supplies electronic components. Each component has an online data sheet. See if you can spot a component that refers to the parameters changing and needing to be burnt in. I can't.
So how did this burn in nonsense start? My guess is that some HiFi hack confused 'running in' - which is a valid requirement of mechanical systems (speakers may well benefit from running in, for example), with burning in - which as I explained above is about failure rates.
As for burning in cables, this only illustrates the paucity of technical eduacation in schools these days.