On the inside of my left wrist. I'm very right hand dominant, so I don't know if I could even do up the strap with my left hand. On the inside so I don't smash it so easily from waving my hands around and bumping into things. Never wore one much, though, and not for years now. I could never get comfortable wearing one, and would just end up scratching and picking at it, and taking it on and off all the time to fiddle with. Most men's watches looked stupid on me, anyway, as I have ridiculously skinny wrists.
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