Whether burn-in is a matter of physics or psychology is hotly contested. I'm willing to believe in it - to a certain extent. There's a slippery slope full of products that fall prey to claims of "burn-in," from wiring to electronic components, themselves. And yet, my experience - time and time again - tells me that headphones sound better after so many hours of use. I've tried to deliberately "burn in" my headphones, by running them day and night, but the best "burn in" I've gotten has come from simply using the headphones over a period of time. This may mean that burn-in is a matter of processing, the same way the brain has to get used to corrective lenses (I can remember how odd it felt soon after I got my first pair)
Whatever the case, you're not going to harm your headphones by either running them a little high or by burning them in too long. On the other hand, the best burn-in I've ever gotten has simply come from continued use over a period of time. One day, you'll be in the midst of a track and find yourself wowed by artifacts you'd not heard before.
