We tend to assume that a perfectly efficient system has no slack.
But in order to maintain optimum efficiency, a little bit of slack is important for whenever the unexpected inevitably happens.
The current supply chain issues are a great illustration of this. A system designed to manufacture goods just in time for consumption (in order to reduce storage costs) is really brittle. If a pandemic strikes, or a ship gets stuck in one of the most important canals, there’s no slack to handle the interruption.
This globalized system of interdependent logistics and production companies quickly starts to fall apart.
The same is true for how you spend your time. If you are booked every minute of the day, you have little flexibility to adapt if something unexpected happens. By maintaining some unscheduled time, you free yourself to more easily pursue a sudden opportunity or troubleshoot a surprising challenge.
And so we’re left with a paradox: A system with slack built into it may seem less efficient, but its resilience helps it win in the long run.