I've noticed this starting with my ipods and continuing with my first iphone. I keep a spare cable at work, in my car, and at home where I keep all my chargers. I use the generics to make sure I have enough. In time these cables always seem to fail. I first get them and the device charges like a charm the moment I connect. In time the cables get a little wonky where the phone will stop charging when the cable jiggles. In time, they'll stop connecting entirely. I check the end, no dust. The phone isn't an issue because it works fine with other cables. It seems like the problem is isolated to the part. Very strange.