Plans are useless.
Planning is everything.
The process of evaluation of a given situation and creating a structure for effective communication between partners is invaluable to any endeavor. And concrete goals and objectives are highly effective in motivating action.
The “Plan” itself begins to become irrelevant as soon as implementation starts simply because the real world environment is always more complex than we can account for in our evaluations. But if we have even just a grasp of the situation and a communication system in place, we can adapt our implementation to the changing environment and still successfully achieve our goals.