I agree with Bill's perspective as to the use of these.There is no excuse for a carpenter or drywall hanger to leave an oversized hole around the box for the electrician to have to deal with.. I never hesitate to call this to their attention, and the attention of their superiors if need be. Sometimes it ruffles their feathers, but who cares. Occasionally I have had to quote NEC 314.21 to them. Then I let them know that the oversized holes are to be repaired or I don't trim out !! No exceptions.
