It depends very much on the environment. If I'm using Python, I'm happy because it has built-in testing modules I can count on. There are also cases where Pyt

It depends very much on the environment. If I'm using Python, I'm happy because it has built-in testing modules I can count on. There are also cases where Python unit tests are worthwhile for other languages. For instance, I've subclassed unittest to quickly run and diagnose arbitrary Unix programs in isolation, and further subclassed it to help launch specific compiled programs under test. If I join a team where someone has already done the work of setting up a reasonable test infrastructure, adding and maintaining tests is often OK. But anything starting from scratch, count me out. :) Sometimes you're thrown into a semi-mature C++ project where they weren't making modules "testable" from the start, and that's way too much effort to retrofit.