[stcredzero]

> I heard a rough rule of thumb to stay away from abstracting anything until you see it repeated identically at least three times, not two.

I used to work in a shop with that rule, and I've mentioned it here on HN. It's still pretty easy to track down and rewrite 3 occurrences. Heck, it's still pretty easy to track down and rewrite 7, though as you let the numbers increase, you run the risk of missing an occurrence, making a mistake when you do the refactor, or the introduction of a confounding "idiosyncracy" in one of those occurrences.

In my experience, 2 occurrences is too little data to justify refactoring around, unless those are pretty hefty chunks of code. 2 occurrences of 2 consecutive lines is definitely too little.

[dllthomas]

I think the focus on counts is wrong. The first question is "are these the same for a reason." If there are two places in the code that need to behave the same or the code is broken, then you should probably pull it out. If there are 100 places in the code that happen to behave the same, but any subset of them could change independently tomorrow, then you might not want to pull it out.

[rdiddly]

Exactly - 3 occurrences is a pattern - 2 is bordering on zealotry.