Exactly. A decent test suite will do two things: 1) Give you confidence that if you refactor something, when you do something silly it'll break the tests and s

Exactly. A decent test suite will do two things: 1) Give you confidence that if you refactor something, when you do something silly it'll break the tests and show you where you went wrong quickly 2) Allow you as a developer to write new things in isolation, so you can run the code without needing to jump through any hoops to see that it's correct I tend to write tests when the thing I'm developing isn't simple/cheap to access. Writing tests should help you do things faster, as well as stopping future you from doing daft things. Writing tests dogmatically however, is a waste, and if tests are hard or onerous to write, it shows that the application is probably poorly designed and architected.