My pair I got last year for Christmas were fine for about 7 months, then started developing small cracks along the struts that run from the actual earphones to the headband. At first, it was just one small crack, which I covered with some tape... but then many more cracks developed.

Basically, the plastic would develop crasks near the pivot point next to the earmuffs, as well as near the opposite end of the plastic struts. Apparently, the force of the metal that lies underneath is just too much for the plastic to handle. Eventually, one side of mine also completely broke around the screws that hold the strut together.

I asked the Bose guy at DEN about the problem, and he gave me the contact info to call and send them in... which, like many people, I didn't want to do. So I went to the local Bose store in Tyson's Corner and mentioned the problem, and the guy said, "Just bring them in, and we'll swap them out!" (of course, I had them with me).

I got the "redesigned" model. The old ones had that bronze color to them, whereas the new ones are completely silver. The key structural difference seems to be that the struts have been reversed, so that the inside (toward the head) surface is molded in one piece with the two sides, with a plate screwed down on the outside surface. Hopefully, this will give the inside surface enough additional strength to resist breaking from the stresses placed along the inside edge from normal wear.