Software Architect's Handbook

Designing for maintainability

In order to design a software architecture that exhibits maintainability, you must reduce the difficulty in implementing changes. Making it easier to implement changes, in large part, means reducing the complexity of the architecture and its components.

Higher levels of complexity make software systems harder to understand, test, and maintain. For this reason, the level of complexity is a predictive measure of some quality attributes, including maintainability.

Evidence shows that modules with greater complexity are also more likely to contain errors. What makes this situation worse is that such modules are also more difficult to test, meaning that it may be more likely that an error will go undetected.

Although ...