Ok, this is an old thread, but I had to come to Head-fi to rant about this issue.
I have had my Grados (SR225i) for 10 years now, in a light use in the home. After 5 years I had the first durability issue, one of the plastic parts was cracking (the one where the metal rod meets plastic). After that it's been downhill with more and more parts getting broke. For example, the wiring (about 10 cm from the cups) got torn, because the plastic in the wiring is quite stiff, that doesn't withstand much movement in the long run. And now, as the final nail in the coffin, the sound is cracking as well - it is disappearing/appearing along the movement of the headphones.
I think they should not behave like this, as the usage hasn't been that tough on them (although 10 years may sound like a lot). Just normal use. I'm quite shocked in fact, at the brittleness of these headphones.
And sorry, if this is bad for Grado (the company). I wish they would listen to this feedback and make some changes though (there would be a lot of them).
I'm now off to buy some "cheap good headphones" which I won't regret too much if they break...