Well to be completely honest with you, I just came from probably the dirtiest environment in the states, except maybe death valley or Barstow
El Paso, TX is basically the desert, and the dirt is evident everywhere you go, in the air, on the streets, in the rain, the list goes on. I normally wouldnt change them until I have at least 15k on them, but due to circumstances, figured it would be best.
Zsteve, when I took them off, the underside was a little brown and a few dead bugs here and there, probably could have gotten a bit more out of them, but to be on the safe side, just said screw it and put new ones on.
And to the others, I understand that its wasteful to throw perfectly good filters away, however, im home on leave and being that my car is my only means of transportation, and had to be at a bbq later on that night (no time to let the filters dry), I just bought new ones.