In-ear, less so, but definitely anything decent in the higher end cans certainly. It helps to make all the membranes and whatnot more supple and such. Despite people claiming it's complete hockum, it's not and what does it hurt to do it anyway?
It's the same with speakers, esp ones with kevlar cones. Best way for them is to make them face each other wire them up in opposing polarity (so they cancel each other out) wrap em in a blanket and turn them up to 11 for a few hours, does them the world of good