When I started subbing, I asked my husband to get me a watch with numbers and a second hand for Christmas. Classes end at strange times (like 11:17) and not all of the rooms have working clocks. Also, you are not allowed to take phones out while you are working with the students.I agree that clocks aren't necessary. I probably fee that way b/c I have the time on my office phone, on my computer in the right hand corner, when I'm out of the office I can see the time at a glance on my cell. There are buildings with huge digital clocks.
I never wear a watch. Althought I do like the white ceramic watches more for the style. I might get one of those.
I don't wear one when I'm not working, though. I get too anal retentive when it comes to time and not wearing a watch helps me to calm down.