Extreme Programming Installed

Can Stories Be Too Big or Too Small?

For planning purposes, stories should encompass a week or two of programmer time. We pick that number to give the customer good control over scope, but also because programmer estimates are pretty good over that range of time. When a programmer looks at a story, rolls his eyes, and mumbles, "Uh, that might be a month, maybe six weeks," we are pretty sure he doesn't really know how to do it. So we ask the customer to split the story.

It's usually easy to break a big story down into two or more smaller ones. Often the story has a very important part and a less important part: That's a good place to split. Other times the story covers several related cases: Consider making each one a story. Customers, don't worry ...