Respectfully, for discussion not argument. You are referring to bidding more than estimating. In standard residential, there is what there is, and since the fixtures are usually dealt with separately you often avoid that pitfall as well only supplying cans, and possibly a couple garage lights and bathroom fixtures, excluding all others unless the plans actually have them on it. You know how many receptacles, where switches must go, what circuits are required, the method of construction, and the basic material being used. Determine outliers, like a well pump, a pool, the method of incoming service and you are done. I don't worry about competing against others, if they don't bid what is needed then they probably won't be my competition for long. If the plans are basically complete, then additional items not realized are changes or can be dealt with as adders.
Now after all that you have to bid. That is about selling yourself and knowing you competition.