I had the Sennheiser CX300 and never did anything to them and a little over 1 month after I got them, they broke. And I don't have the receipt, so I'd have to pay to have them fixed. So now I'm looking for another pair, and when I bought the Sennheiser I was debating between them or the Etymotic. The worst thing I ever did to the Sennheiser is to wrap them around my Touch. I didn't even wrap them tightly, just enough so that they would stay wrapped around it.