A little over a year ago I came to the realization that I'm pretty abusive to headphones. not that I mean to be, it just so happens to work out that way. I sit at a desk all day, I run, and I will also listen to stuff on a regular basis outside of those two things. Whil at work I pretty much listen to music, radio, podcast, or whatever the entire time, I don't go to very many meetings, and have to take the headphones on/in and off/out several times during the day. This causes the headphones to wear down a lot faster then you would think.
I think that the longest I've gone has been with my current setup and that is because I had more then one set. I had the standard iPod/iPhone set that I would use for play and etc. Love those headphones, but I had a better set that although looked a bit DJish were probably the best set of headphones I've ever had. Granted they seemed expensive because I usually just buy the $10 sets at Walmart when I have to buy more, but cost between $40-$50 and where made by skull candy.
I'm about to the point where I'm going to have to get new ones again because I'm down to just the apple ones. I would really like to get a good set of wireless headphones, but those usually cost quite a bit more as do the Dr. Dre headphones which seem incredible, so I may just end up getting some skull candy ones again because they make a pretty good set of headphones, and if your ever looking for a good pair of headphones regardless of type (over ear, in-ear) then I would highly recommend a pair (or two) of skull candy headphones.