Software Design X-Rays

It is not well to make great changes in old age.

Charles Spurgeon

Chapter 5The Principles of Code Age

In this chapter we explore package-level refactorings as we see how to organize code by its age. We measure the age of code as the time since the last modification, so that we can separate code we recently worked on from old and stable parts. Code age is a much-underused driver of software design that strengthens our understanding of the systems we build. Code age also helps us identify better modular boundaries, suggests new libraries to extract, and highlights stable aspects of the solution domain.

You use code age analysis to evolve systems toward increased development stability, where the resulting structure offers lower cognitive overhead. ...