Why is it important to measure maintainability and what are the best ways to do it?

Being highly maintainable is the key to reducing approximately 75% of most systems' life cycle costs. Software maintainability is defined as the ease with which a software system or a component can be modified, to correct faults, improve performance or other attributes, or adapt to a changed environment. There exist metrics that can help developers measure and analyze the maintainability level of a project objectively. Most of these metrics involve automated analysis of the code. In this extended abstract paper, we addressed the importance of understanding software maintainability, explored some of the best ways to measure maintainability and briefly described a comparison study we conducted between automated maintainability metrics and human-assessed maintainability metrics through a controlled experiment by performing change-request modifications on open source software (OSS) projects.