Wristwatch Habits

Do you know how to tell whether someone is lefthanded or righthanded when you first see them?

If they are wearing a wristwatch it can be a giveaway, not 100% of the time but more than likely they will have the watch on the opposite wrist since it is out of habit that they will put the watch on using the hand they use most therefore it will be on the other wrist from their writing hand.
I’m talking about just looking at the person and not even watching them use their hands

I can usually tell after watching someone for a few minutes. Clues are which hand are they most likely to use to reach for objects, which hand they use to wave with, and which hand they gesture with. Those will usually tell you which hand a person prefers.