Hello, I have a quick question concerning the Nikon warranty slip. I was wondering if my warranty will still be valid if I don't mail in the slips. I have always just keep all my boxes, with all papers inside. Should I mail out the slips? I just bought a new lens and it had an envelope inside that said: " 1 yr. Warranty + 4 years extended service" but it said the 4 years was only valid if I mailed in the slip?? Is this true, and what are your opinions on this topic? Thanks, --Mark