Plans increase follow through.
Feelings are unreliable.
Sometimes we feel like we want to do our behavior, other times we really don't.
A plan creates the conditions for us to do a behavior regardless of how we feel.
By mindfully choosing a day, time and location for our behavior we take a very large step toward the probability it will happen.
In the moment of choosing the day, time and location, we imagine it happening, we mentally rehearse it, even if only for a few seconds.
That tiny moment of imagining your behavior in time and space is crucial and significant. It's extraordinary how such a small simple action can have such massive effects.
A plan is a set of commitments. It represents what you aspire to and how you intend to get there.
We are accountable to these commitments, and without a plan, there is nothing to be accountable for.
Here is a Harvard study on the power of plan making.