Take off the covers/protectors for the bottom front fenders, pull the liner out a bit and look inside. Mine was filled with leaves and dirt. FILLED. I bet they'd rust out if left unchecked. I cleaned them out and put some rust preventative paint in there.



What came out:

 

Thanks for the tip! I hope I can keep my '08 looking as nice as your's does.

 

I cleaned mine out when I did my header swap. Found a nice rusted razor scraper some previous owner/mechanic must have lost. Mostly dirt in mine.

 

Mine have some rust in that spot. Replacing fenders and front bumper soon despite only having 54k.