Running your components and cables for some arbitrary length of time when they are first purchased isn't helpful, but this article explains what is.
Quote from the article:
“With even simple home theater systems now needing universal remotes [Hack #84] and calibration to perform well, a lot of well-meaning folks have passed around some home theater myths, or at best, misunderstandings. One of these is that you need to burn-in your equipment. Burn-in is a term used to refer to running your gear for some arbitrary length of time, usually several hours, to help it perform properly. You’ll most commonly hear about burnin when talking about speakers, which often can benefit from this sort of treatment. “
