I've had my HD 598s since 2012 or 2013 I believe. There's small cracks near the headband adjustment (common issue I believe) but they're still great. Of course, I did have to change out the muffs once.

I imagine I won't be replacing them because they break, but rather because I want to get something better. However, the 598s sound pretty great to my ear so there's not really a huge incentive for me to get anything new.