I say, "To each his own" on this one. I've had the optional factory cabin filter on my LX since I bought it new 5 years ago, and I see the crap that it catches. I put one on my WK and won't have a vehicle without one now. I also concur with "fatfreddy's" reasoning. I recently had to pull the A/C evaporator core from my 90 Grand Wagoneer for this very reason. Of course, back then there were no filters, but it was plugged almost solid and the A/C didn't cool well, even though the rest of the system was sound. This filtration is rather cheap insurance against having to tear the system apart later, IMO.