When I was in college, we had a very old-school distinguished Spanish professor (Ph.D., University of Alabama) who traveled and shopped for his clothes and shoes in NYC, Paris, Rome, and London -- just a really classy guy in many ways. He always told us young men that a gentleman always wears a watch that's appropriate to his activities for the day and that you're not really dressed if you don't have your watch on (not counting playing sports or heavy manual labor, of course).
Now I teach at a college, and about 90% of college guys use their phones for telling time and do not wear a watch. I occasionally remind them that one trait distinguishing a boy from a man is that a grown man wears a watch but a boy doesn't. I say this to the young men in my classes in a humorous spirit, but it's interesting to see how many of them wear watches to class from then on! I will begin to see on their wrists Fossils, Citizens, and a few Invictas, but at least they're getting started on the right and gentlemanly path!