Traditionally, the cost of change curve said that if we detect the need for a change early, it costs less to make the change than if we detect the need late. I tackled that curve by saying, let's almost intentionally make mistakes so we can practice correcting them. That practice will help reduce the cost of making changes late.
Our feeling was that the limiting factor on any change was not when it was done, but how much thinking was required.

A Conversation with Ward Cunningham (2003) - Working the Program