I introduced my four year old gelding to clippers just a little while ago. Today was the first time he's ever heard, seen, or been around clippers.
I couldn't be prouder, either! He stood perfectly still and allowed me to finish his mane, clip the longer hair on his lower legs/fetlocks, clip his whiskers, and he even let me clip his ears!
Didn't try to get away or anything... he acted like he'd been doing it all his life. Even my mare, who is sixteen, doesn't stand that still around clippers (or anything that 'buzzes').
Just had to share, he made me so proud!