In a Kanban system you introduce WIP limits at each step of the value flow. This means, that if you get stuck at any one step in the flow and things are not moving forward, then all those who operate in earlier stages of the system enter a holding pattern. If you’re explaining Kanban to managers or executives, this is usually the point that makes them take a sharp turn off of the Lean highway! They mentally write off the whole concept of Kanban because “they don’t want anyone sitting idle.” What skeptics call “sitting idle” is often referred to as slack in the system.
These executives and managers may not realize it, but they are turning their backs on the very thing that could make their company and its products more innovative and stable. If you are working nose-to-the-grindstone 100% of your day on new initiatives then you have no time to think, to reflect. Therefore, you have no time to consider innovations or improvements to your products and services. These developers struggle just to keep your head above water, to survive. They often, if we’re lucky, have lists of things they notice that need to be improved or defects that need to be fixed. Many of those things will never get the attention they need. That doesn’t sound like a recipe for success, does it?