I saw this in a job posting the other day, describing the work environment at the company:

We pair a lot, but not all the time. We test a lot, but not all the time. The key is being able to explain your practices with rational argument.

I love this. There are practices like testing that I hold in high regard, but nothing should be done all the time. As the posting says, “the key is being able to explain your practices with rational argument.”

Can you explain why you do something like TDD? That’s probably easy for you. But can you explain when you shouldn’t use that practice? That’s a little harder to do, and maybe because you’re holding onto some ideal that says you should test all the time or have 100% test coverage.

For every idea or practice that you find valuable, you should also be able to explain when it doesn’t apply. If you can’t explain when not to do it, I would say that you don’t really understand when and why you should use it.