A plan made is a promise to the future self, how he will act.
The putting forth of a plan allows one to do the following:
First, test the adequacy of ones planning. What was missed? What was inadequately prepared for?
Second, tests the willingness to keep promises. Will I do what I say? We’ll see. Much is learned about me by me by my unwillingness to do what I say I will do with myself.
Third, allows for a reduction in choices presumably in conditions where good choice-making is either difficult or inefficient. Choice-making takes time and is influenced by feeling in the moment. Why not choose now and avoid either the passion of the moment, or the arresting of action for the contemplation of how to choose?
Fourth, a plan is only worthwhile for providing guidance. The guidance is superfluous unless there is a prediction that the one guided might misstep. The adherence to plan, the keeping of the promise to act in a particular way, requires restraint. The strengthening of inner restraint necessary for sticking to a plan can only enhance future action.
So, make a plan today. See how you do.