I am working on a "spaghetti-code" project, and while I am fixing bugs and implementing new features, I also do some refactoring in order to make the code unit-testable. The code is often so tightly coupled or complicated that fixing a small bug would result in a lot of classes being rewritten. So I decided to draw a line somewhere in the code where I stop refactoring. To make this clear, I drop some comments in the code explaining the situation, like: class RefactoredClass { private SingletonClass xyz; // I know SingletonClass is a Singleton, so I would not need to pass it here. // However, I would like to get rid of it in the future, so it is passed as a // parameter here to make this change easier later. public RefactoredClass(SingletonClass xyz) { this.xyz = xyz; } } Or, another piece of cake: // This might be a good candidate to be refactored. The structure is like: // Version String // | // +--> ... // | // +--> ... // | // ... and so on ... // Map map = new HashMap<String, Map<String, Map<String, List<String>>>>(); Is this a good idea? What should I keep in mind when doing so?