Maintainability is not just about you changing your code later on; it's about someone else trying to understand what you were thinking when you write it.. and t

Maintainability is not just about you changing your code later on; it's about someone else trying to understand what you were thinking when you write it.. and then change it. Tests make that process way easier. You can add your new feature without wasting time to understand everything else and still make sure it's working. If it's your own project, meh, you know your stuff. You even know all the hack you did to gain time. I see tests as a documentation that shows me what's working. Reading tests (high level ones) is usually the first thing I do when starting on a new project. Comments change over time.. documents aren't updated.. people leave.. but tests remain. If the test passes, it doesn't mean everything is perfect, but at least you know that these things work.