Comment by dragonwriter

> it is _much_ easier to refactor copy pasta code,

Its easy to refactor if its nondivergent copypasta and you do it everywhere it is used not later than the third iteration.

If the refactoring gets delayed, the code diverges because different bugs are noticed and fixed (or thr same bug is noticed and fixed different ways) in different iterations, and there are dozens of instances across the code base (possibly in different projects because it was copypastad across projects rather than refactored into a reusable library), the code has in many cases gotten intermixed with code addressing other concerns...