Good question. There isn't a hard and fast rule, because as you noted the "fashion" sense is to crop it at the wrist, but some old-school practitioners like about an inch longer. The most important thing is to get it done correctly (from the armhole) so that it doesn't affect the buttons. I go for the fashion look personally. If it's that cold you should be wearing gloves.
9/17/14 at 7:33am