There’s a powerful graph that illustrates the importance of safety capacity by explaining how waiting time goes up with increased resource utilization.
Imagine you have a solitary cashier at the checkout machine. This graph explains that waiting times are going to more than double when the cashier is busy 80% of the time. It doubles again if his utilization goes up 90%.
Why? Because delays can be easily caused by sudden fluctuations in the queue. If a large family brings a massive order, everyone behind them in the queue will simply have to wait. So, if a retailer runs their operation with their clerks at 100% capacity, you can be sure that the customer experience will suck.
The same goes for our lives. If we organize ourselves such that we always find ourselves running at 100% capacity, it is inevitable that things will go awry. Work doesn’t arrive at a constant rate – an emergency project is bound to show up and, if we’re running with no safety capacity, that will be a problem.
Additionally, we’ll never have the bandwidth to deal with other sorts of fluctuations that may occur outside work – an injury, a family member that gets sick, a friend that needs help, etc.
Always build in safety capacity.
