@ucbalumnus: Not really a factor as a certain level of dress is expected in biglaw & many, probably most, use public transportation. What is a “watch” ?
Big 4 dress is often quite casual, although it varies by location. But, no, none of these are factors.
P.S. Although the reference to shoes does remind me of the common description of “an accountant with a personality”. How do you tell an accountant with a personality ? He stares at your shoes when talking to you.