Outside.
But, is the rule the righties wear it on the left, and vice versa for lefties. The purpose being to minimize banging on the watch, I presume.
Yeah, you're supposed to wear it on the opposite arm of which you write, so you're not banging and scraping your watch against the table top.
I've had the same watch since I was 14, and I love it. However, the battery died back in the spring, as it does every 2 years, but I haven't gotten it replaced yet. I wore it for about a month even though it had stopped ticking. It's been through hell over the years and looks like crap. The glass is cracked, and some of the gold details have been rubbed off. I'm considering taking it to a jeweler and seeing what they can do to restore it.