I buy Etymotic in-ear monitors, pretty damn expensive.

Despite thorough personal grooming and only having them at a studio desk, the part of the cable that wraps around the top of the ear will still get eaten through to the copper by the oil on my ears after about two years.

Shitty or not, headphones—at least the ones that see thorough use—are consumables.

A good headphone design makes the parts that wear out replaceable. Bose does this with some of their stuff, as do others, I would guess. It should be considered an important part of the design.

I was buying earphones in the 20-30 dollar range. Yes, they were cheaper (though not the cheapest), but I didn’t want to spend a lot of money on headphones on my grad student budget.

How much should I expect to pay for quality headphones with the jack that last?

The Sony xbs can be had around $40-50 online, sound much better than cheapies, and cables last over a year. I usually grab a pair or two every xmas when they go on sale. My current pair has made it two years and been through the wash.