Добрая заметка: Refactoring is a Necessary Waste:

By seeing Refactoring as a necessary waste, then a developer will minimize refactoring; that is only refactor code that no longer meets the requirements of the user. This means, when you are coding away and you see a method in the class you are modifying that "smell's bad" but has no direct connection to the requirement you are working on, you leave it alone.

Здравый смысл в этом есть...