I have had m50x (hinges broke, reviews say they are strong) yamaha pro300 (headband broke the first 3 months) almost bought shure srh840 (weak hinges) i have had countless Sony, akg, audio-technica headphones, no reviews said they wear buit like cheap crap.
Now I have had these he4xx for the last 3 years, I also thought they might break, many reviews say they are built badly...... I don't know if they are being paid to say they are bad, or if I got a revised pair, but I accidentally sat on them twice, dropped them about 3-4 times, was rained on while wearing them once and they are still going strong
But I have quit drinking alcohol since I've gotten them, I noticed a lot of things break more often when you have a drink (not many drinks, just 1 or 2)