Just did this again today, after doing it in April of 2015. It probably could've waited several months more, but since I was rearranging stuff in the glove box, I was just about halfway there anyway. It's even easier after you've done it once, and since I had gotten a three-pack of filters last time, I already had one on hand, and I still have another one left for the next time. At $11 a pop (and free DIY installation), it's nice to freshen up the cabin air, plus there was a little debris, mostly pine needles, in there I took out.