"...I never understood why it was better to do things backwards...The idea behind TDD is that you’re able to write a test because you sit down and think about t

"...I never understood why it was better to do things backwards...The idea behind TDD is that you’re able to write a test because you sit down and think about things first...." Yeah no. You have been instructed poorly. It's not your fault. Yes, you have to think about things, but that's not the real purpose of TDD. Just like making a good design, it's a side effect. Straight coding is doing it backwards, as odd as that sounds. The reason is that the computer never lies, but it's really, really easy to lie to yourself, forget things, misunderstand your own variable names, and so on. When you're coding, you'll make all kinds of errors. The computer will not. So wouldn't it be better to have the computer constantly checking on you to see if you're making any new errors? Better still, not only will it check on you, it'll check on everybody else who touches the code too. There are domains in which TDD does not make sense. Exploratory coding, like you'd do in startups, for instance. Small pure functional code. Academic learning. In each of these cases you are still doing TDD, it's just you're not coding the tests. You never get away from TDD, you just sometimes hide it or pretend it isn't happening. There's a test, it fails, you write code to make it pass. In other cases, such as any non-trivial mutable OO commercial code that is going to be around for a while, not using TDD is malpractice. Whatever small hit you may take on initial productivity is insignificant compared to the endless amount of money you may spend later on maintenance. Plus, I'm not so sure it's inefficient to begin with. Instead, I think a lot of coders code in an inefficient way writing code that is difficult or impossible to test. Once you start using TDD, you're going to have to come to terms with that and un-fuck your code. That's probably going to suck. Best to do it earlier rather than later. (Long discussion here about what to do with legacy codebases)