And the test covers much less surface area than most manual tests. For code that's expected to be stable for a LONG time - sure, write lots of good tests. For

And the test covers much less surface area than most manual tests. For code that's expected to be stable for a LONG time - sure, write lots of good tests. For code that breaks at someone else's whim, which has a small shelf life, or which has a large surface area, think really, really hard about whether the test is actually going to be worth it.