My take on their durability is that my hinges were fine around a year ago when I sold my personal pair to a good friend. :) Sorry I can’t provide more info than that!
Pioneer offers a 1-year warranty, so if they break during that time frame you should be covered.
I’ve run into defects every now and then, with unglued headband pads or broken adjustment sliders, but I’ve never personally had an issue that was outside of warranty. The only issue I’ve ever felt was truly widespread was that exciting 1000X plastic cracking issue.
Thanks for the note though. I’ll keep an eye on it, and if others report in about it I’ll perhaps write on it in the future.