Because it exhibits the same characteristics as when I got it (not that I feel any particular compulsion to "back up my claim"). I can plant my thumb directly on it and not see a fingerprint. Exactly as on my much newer 4S. When it finally does show some smudging (which takes awhile), a single wipe or two makes it all go away. That qualifies as completely intact to me, and therefore it DIDN'T wear out in just a few months. Thank you.
Have you done anything to preserve this? Do you make sure you have very clean hands before use or have a special method of cleaning the screen. I'm asking by the way not to make digs or anything. I'm genuinely interested as both my 3GS and 4S oleophobic coatings wore off within months. Same as with everyone friends iPhones post 3gs that I know. Theres definately no way i still have one on my current iphone 4s anyway (Bought in february) it can't seem to get enough fingerprints!