Confidence & Unit Tests

Why do we waste our time with these stupid unit tests, some might ask. Well, if your system's requirements can change on a dime then I'd say (besides the initial measure-twice-cut-once rule) that the next most important thing you can do is have an automated suite of tests that can ensure your "tiny" "quick" code change doesn't have massive negative impact on the rest of the system. An automated build that runs unit tests covering most of the code base gives developers confidence to change the relevant pieces of source code and get quick turnaround times for new features and bug fixes. Yes! Quick turnaround times because the code was all already under test. I hate to say it, but "agile".