Test driven development. Making your tests first, or at least early, helps you mentally nail down what you want your software to do. It also helps you think def

Test driven development. Making your tests first, or at least early, helps you mentally nail down what you want your software to do. It also helps you think defensively early-on about corner cases and race conditions. But that isn't really where the biggest benefits lie. When you come back to that code a year later and have to make changes to it, but have forgotten how it works, having all the tests pass with good coverage provides a significant (but not absolute) level of confidence that you didn't break anything. Given that so much development time is spent editing/updating code, rather than writing it from scratch, this can be a huge speedup in productivity.