I changed out the cabin air filter on my wife's car today. I was looking through the owner's manual at maintenance items (knew the engine air filter was needing changed) and noticed that the cabin air filter is supposed to be changed every 15k miles. Her vehicle has around 34k, so I figured I better change it. However, I can say a feel better after seeing the picture of that filter you posted. While hers was dirty, it didn't look anything like that.