Good Morning
The marginal effect is similar to a planning by scale, you must program a routine that allows you to progressively meet the objectives, it is up to you, the time you want to invest to achieve your goal.
This same marginal effect is applied to the economy, in the form of reducing costs progressively, in an opportunity, I read somewhere, that a large company or travel agency reduced its costs by more than one million dollars, only, removing, from their salads, that serve the users of airplanes, an olive, for the clients could have been something unimportant, since, after all, it was only an olive, but for the travel agency it meant a reduction significant in its costs.
Everything depends on the planning and the opportunities that are presented to us, in order to reach the objectives.
Regards ...