Code is not clean : code is cleanable. What is clean today might not be clean tomorrow (Robert C. Martin, author of the book "Clean Code") Trying to evaluate c

Code is not clean : code is cleanable. What is clean today might not be clean tomorrow (Robert C. Martin, author of the book "Clean Code") Trying to evaluate code cleanliness in isolation is a waste of time ; as it strongly depends on the way your requirements evolve (but it's not subjective). You only need abstraction points at the frontiers between parts of your requirements that change at different times. Duplication is better than a wrong abstraction (Sandi Metz, author of Practical Object Oriented Design in Ruby). Trying to religiously factorize every structural similarity you can find, for the sake of the almighty DRY principle, without taking into account how business requirements evolve, is counterproductive.