I've replaced my cables once (6 months in), this wasn't so much a cable issue as a wear and tear issue. The stock cables come with a straight jack, which whilst i think whilst looks nice with an ipod, is weak. It puts adverse pressure on the wire section that connects to the jack, if you wrap them around the ipod when not in use like me (i do know people who stubbornly unplug after use everytime and put it into the metal case but for me, that's just not practical) or sitting down, leaving it in your pocket while playing and the player becomes horizontal (if jack is located at top or bottom of player so the wire gets bent acutely), you will eventually get failures in the wire.
It's a known issue, and that's why all replacement cables have a L shaped jack. The normal issue is failure from the section you wrap around your ears (my friend has had that issue and replaced it in a time frame of just over a year in each instance) as that part of the cable receives the most punishment in terms of bending etc. The replacement clear cables I have, seem durable and fairly well made for a $20 replacement (although logitech WILL replace them free for you inside warranty), I don't see them breaking for a while and look great in clear plastic, you can see the dual silver braided wire underneath, would recommend them as part of your purchase, just to give yourself a cheap option to change the look.Or you can go for null audio or other branded wire, if you believe the stuff on wire upgrades affecting sound. but tbh at $20 a pop, it's no biggie, I'd get 2 backups just in case at the start, and you'll have sustained use of them for a long long time (changing the cable is as easy as unplugging the old ones and plugging in the new ones).
