When you bid on a job, I am sure that a set of plans were given to you. Any wiring methods,materials,service size,grounding details,etc.. should be done according to the plans, However for those that wish to make extra profits just do not follow the plans.For example, use NMC instead of a Metal Raceway, install (50) circuits instead of (100). so when an if the wiring system fails because the plans were not followed, who is to blame, the AHJ, The General,or the Electrical Contractor ?