[hinkley]

I don’t think there’s an accepted set of concrete criteria for making software that can absorb major design changes later without a great deal of effort and stress. How you write code that can accept an abstraction layer at the last responsible moment.

Some people have an intuition for it, but it’s sort of an ineffable quality, buried in Best Practices in a way that is not particularly actionable.

So people having been scarred by past attempts to refactor code reach for the abstraction in fear, just in case, because they don’t know what else to do and it’s not written down anywhere, but abstractions are.

[Symmetry]

I've found that refactoring to fix a lack of abstraction is usually easier than refactoring to fix the wrong abstraction.

[hinkley]

Definitely. Among other things, this is akin to Work Hardening.

Refactoring tries to avoid this but the slope of that line can still end up being positive and you can’t refactor forever unless you’re very careful. And “very careful” is also not yet quantified.