Extreme Programming Installed

During Project Flow, Estimate by Comparison

For an ongoing project, the work all takes on a kind of familiarity. Part of this is because one story is often just an elaboration of another closely related one. Plus, since you are keeping your objects clean and clear, you become more and more familiar with how to use them, and new requirements fall into place in familiar ways. During the flow of the project, take advantage of these facts.

Look at the story. What stories already implemented is it like? Does it access the database similarly to that one about the tax lookup? Does it produce a report similar to the one about parking tickets? Does it seem like a specialization of the purchasing business rules? As you think of stories that seem similar, ...