The lens on a Note 3 is covered with glass. (I don't know if it's Gorilla Glass 3 or soft window glass, but it's glass, and looks like about $5 to replace.)
I have an iBlason case, but the glass over the lens still looks pretty unprotected.. But I don't drop muy phone down on a table without looking to see what's there. (I don't drop it at all, I place it down gently.)
I take some pretty tight closeups and blow them up a lot and, aside from the fact that I'm blowing them up a lot more than I should for a camera with this resolution, there's nothing showing from the glass. No dirt, no nicks and no scratches.
The lens on my old V551 (which has been treated more like a Bic pen than a phone) still takes clear scratchless pictures. And that's before Gorilla Glass, before umpteen pixel cameras and before I worried about my phone and my keys being in the same pocket. For years.
I have a 500mm reflecting lens for a Canon that has a scratch on it (it cost more than any cellphone on the market today, and a dollar was worth something back then), but that's the only camera lens I've ever had scratched. ("Had scratched" - and he paid for a new one.)
I take more care of my phone's battery than I do of its camera lens.
