Simplicity requires more work at the beginning of a project to reduce an idea to its essence and more discipline over the lifetime of a project to distinguish good changes from bad or pernicious ones. With sufficient effort, a good change can be accommodated without compromising what Fred Brooks called the “conceptual integrity” of the design but a bad change cannot, and a pernicious change trades simplicity for its shallow cousin, convenience. Only through simplicity of design can a system remain stable, secure, and coherent as it grows.
