I work as an artist so this is superficially worn ( see pics of my body some of the black paint has worn off around the lens. Since it wasn't my lens of choice and I always had my polarizing filter on over the outer lens, it is scratch free - at least from what my naked eye can see.  I also included photos I took with the camera with the filter on and with the filter off.  The poloraizing filter has plenty of light scuffs across the lens.  You mostly notice this when the sun hits and causes small flairs (see pics 8 and 9).  You can see the difference between when I used the filter and did not use it.

*10-24mm lens

*polarized filter

*sun guard

*lens hood

*lens cap for the back

6 - pic of lens with out filter

7 - pics made by lens with out filter

8 - pic of polarized filter

9 - pics made by lens with polarized filter

Please ask me any questions - I'm happy to help