“The planner must be right in his timing of 10 or 20 separate developments, all of which must arrive at the same point at the same moment lest the whole plan collapse. The planner stakes all on an unbroken series of 20 rolls of seven.” — The New Society
This first quote warns us that each additional date in the schedule exponentially increases the risk of variations in the schedule. This is not a call to reduce the number of deadlines.
“Unless we build expectations into the planning decision in such a way that we can find out early whether they are actually fulfilled or not – including a fair understanding of what are significant deviations both in time and in scale – we cannot plan. We have no feedback, no way of self-control from events back to the planning process.” — Management: Tasks, Responsibilities, Practices
Targets are control points. Monitoring and managing deviations to the schedule requires that there enough control points to catch the deviations as they happen. This is one of the objectives of breaking down the deliverables for the WBS.
The Best Plans Are Incomplete Plans