I keep my iPod in my back pocket which puts pressure on the housing where the cord meets the jack. I’ve had several pair fail on me when the wires in the housing came disconnected from the jack. Is there any way to reinforce the jack to prevent the cord from flexing so much and pulling away from the jack?
You can reinforce that part with some heatshrink tubing. But I would be more concerned about the socket of the iPod getting damaged rather than the headphone jack. You should disconnect the jack when you put the iPod in your pocket.