The One-Thirds, Two-Thirds Rule
Time is the single resource which can never be replaced or reused.
It is imperative that leaders strategically utilize their time effectively so that:
Quality plans are developed.
Clear instructions are provided to subordinate staffs.
Subordinates have enough time to effectively complete their assigned tasks.
Plans can be revised, if necessary.
Use 1/3 of the time to plan.
When looking at a planning timeline, consider how much time you have from the moment you receive the task to execute a particular mission (or activity) until execution commences. No more than one-third of this time should be used to plan for your mission. During this time, you should be exercising the first seven steps of the Troop Leading Procedure (TLP):
Receive the mission.
Issue a Warning Order.
Make a tentative plan.
Initiate necessary movement.
Complete the plan.
Issue an Operation Order.
What if you do not have the necessary details to complete the plan? The best practice is to complete as much of the plan as possible, issue your order, and come back to revise the plan (via Fragmentary Order) later as you obtain more details.
Use 2/3 of the time to prepare.
During this time, your staff—along with their subordinates—should be working to prepare for and finalize any outstanding details of the upcoming mission. This time is best spent conducting training briefings, walkthroughs, rehearsals, and, if able, full-scale exercises. This is when your team needs to identify its strengths and weaknesses so that they can arrange for and conduct any necessary remedial training.
A common mistake made by leaders and planners is to consider the mission as part of the two-thirds time allotted for preparations, which is not the case. This time is intended to have prepared for the mission, with your mission start date/time ("T-Minus Zero") as the beginning of your execution.
Be careful to avoid "eating up" the time you have by delaying out your planning! This can result in a lack of time to adequately prepare and, thus, results in a poor-quality execution of the mission.
How to calculate your planning timeline:
Subtract your Mission Order Received (MOR) from your Mission Start (T-0) to determine the Total Time you have Available (TTA). This can be minutes, hours, days, weeks, or even months.
Divide your TTA by 3 to create thirds. One-third of your TTA is for planning. The other two-thirds of your TTA is for preparing.
TTA ÷ 3 = Planning Time Available (TA-PLAN).
[TTA ÷ 3] x 2 = Preparing Time Available (TA-PREP).
To provide an example:
You receive the order to conduct an activity on 30 July. Today's date is 01 May. This gives you a TTA of 90 days to plan and prepare for your activity.
You have a TA-PLAN of 30 days, which means your plan should be completed and distributed no later than 31 May.
You have a TA-PREP of 60 days, which means that you should begin your preparations no later than 01 June and conclude no later than 29 July.