Master the art of refactoring with five essential principles, including refactoring before new features, ensuring test coverage, applying incremental changes, and reducing tight coupling between classes.

Refactoring is not merely tidying up—it's a disciplined process of restructuring existing code to improve its non-functional qualities, such as readability, complexity, and extensibility. When done correctly, refactoring is vital for preventing code degradation and keeping a project healthy. Here are five core principles to guide your refactoring efforts:

1. 1. The Golden Rule: Refactor Before Adding New Features

   Before introducing new logic, take a moment to clean up the area of the code you are about to touch. It is much easier to integrate a new feature into a clean, well-structured piece of code than into a confusing legacy block. This practice ensures you never build on top of technical debt.

2. 2. Always Have a Safety Net of Tests

   The cardinal rule of refactoring is that you must not change the code's external behavior. Therefore, **unit and integration tests** are mandatory. They act as a safety net, instantly alerting you if your internal changes inadvertently break existing functionality. Never refactor a block of code without sufficient test coverage.

3. 3. Apply Small, Incremental Changes

   Avoid massive, monolithic refactoring commits. Instead, apply refactoring as a series of small, isolated changes—each focusing on one specific "code smell" (e.g., extracting one method, renaming one variable). This makes your commits easier to review, debug, and roll back if necessary.

4. 4. Follow the "Rule of Three"

   The "Rule of Three" (from Martin Fowler) suggests that the first time you do something, just do it. The second time, you might feel a pinch, but proceed. The **third time** you write similar code, recognize that it's time to **refactor** and abstract the duplicated logic into a reusable function or class method.

5. 5. Decouple Tightly Coupled Classes

   Highly dependent classes are difficult to test and maintain. Use **Dependency Injection (DI)** and design patterns to reduce coupling. If changing one class forces you to change ten others, it’s a clear sign that refactoring to reduce dependencies is needed.

💡 Refactoring is continuous maintenance, not a scheduled chore. Making it a daily part of your coding process will dramatically improve the lifespan and quality of your software.