[hitchstory]

>However, very few developers follow this approach religiously

I do it pretty religiously. There are 3 exceptions:

1) I'm doing a spike (i.e. what author calls exploratory code) in which case, probably this code is getting disposed of. This is the one main exception.

2) I'm just tweaking a config value/printed message/something else surface level.

3) The cost of building test infrastructure is prohibitive (if it's a long running project I will aim to keep building that infra until it is possible though...).

That's it. As far as I can tell there arent other scenarios where it isnt a good idea.