[jbrains]

I see a lot of comments here of the type "You have to know when to refactor". I don't do it this way. Instead, I rely on a willingness to undo a refactoring when I see that something else might work better -- and even to undo that when I decide that I've got that wrong.

I have no problem extracting as in "WHEN REFACTORING GOES BAD" -- although I might wait for a third copy because removing the duplication -- because I want to see whether a useful abstraction would emerge. On the other hand, as soon as I recognise that one of those copies wants to change in a way that the other does not, I'd simply inline the method and let them diverge. I don't consider this a problem.

It seems as though some programmers believe that, one they extract something, it needs to remain extracted. No. It's only "cargo cult refactoring" if you stop thinking.

Most importantly, refactoring is experimentation. It's a kind of Mechanical Turk-based genetic programming-oriented style of designing, except that you have heuristics you can follow. That means that you'll go down the wrong path. THAT'S OK! as long as you allow yourself to backtrack. Remember: refactorings are small, reversible design changes. That means not just that one can undo them, but that one is willing to undo them.