The strange thing is, I don't listen to my cables while it's burning in. I listen to one reference song at 0hours, 50, 100, 150, 200. 50 hours is around a 5 days, so I don't think it's my brain 'adjusting' that's making a difference in my case.
Further, I always ask this whenever someone brings up placebo. If it is indeed placebo, but it does work for the individual (cure illness, perceive better sound) then wouldn't that mean placebo is a good thing? If, hypothetically speaking, custom cables were really meant to induce placebo, and that there is no factual improvement, but the individual perceives a better sound through placebo, doesn't that mean the cable is technically doing its job? Gotta think about this one. :P
I do note that I didn't perceive much, if not any, burn in difference with the ES5. I thought it was opening up, but it wasn't. :P
Yes, but the point is that the same job could be done using a much cheaper cable. So if somebody handed you an upgrade cable and told you it was the $400 silver poison toxic venom whatever cable, but really it's just a stock westone cable, you would hear improved sound and be happy as ever. No reason to pay the premium if it's a placebo.