I've had good experience with warranty/support channels, so it hasn't cost me much money--just a ton of time and frustration. I currently use Klipsch IMAGE S4 headphones, which I love, but my 3rd pain in the last 2 years just started malfunctioning.
Typically what happens is: Various frequencies start to cut in and out as I move the cord around near the jack. I don't wrap my headphones around my PMP. They do catch on something from time to time as I am walking around/stand up from my desk, causing them to get yanked out of my ears. But that sounds like something that must happen to anyone.
Is this just a normal part of being a headphone owner, or can I do something better?