There has been som general hubbub about establishing WIP limits in the Kanban community latly, some have gone so far as to claim that it is wasteful. Or more exactly that they are wasteful since if you're mindfull you can see the same bottlenecks without them. And theoretically I think that is true. But this is one of thoose times theory just won't help.
In my, not so humble, oppinion establishing WIP limits helps us the same way a budgets do. It help us set clear priorites and makes us think about our general goals. It also works as a clear leading indicator for when things are getting out of hand. One could make the claim that having a budget is waste, and if you're really disciplined I guess that is a viable option. But for me, it's not that I strictly need it, it's just way simpler than the alternatives.
Twitter via @hiranabe provided this gem:
Kuroiwa-san(ex-Toyota mgr) concluded speech by emphasizing "Thinking for yourself in your context" is the heart of Lean
This is another very tangible postive effect of imposing limits, they help us establish context. The heart of lean and agile processes is thinking in context, anything that helps us faster establish context and be present have a great positive impact on the speed of communication. Thereby helping us improve, reflect, adjust and evaluate. That in turn helps us deliver more value faster, and sustain those improvements over time.
Thinking is not the key, thinking about the right stuff is. Establishing context is vital for that.