Refactor Smart Today, Move Faster Tomorrow - Part 2: Plan Your Refactor Step by Step

So, you’ve confirmed that your refactor is necessary. Now it’s time to plan it right - because a poorly scoped or unstructured refactor is a trap that can drain weeks of work and leave everything worse than before.

Let’s break it down.

🎯 Choose the Right Strategy

There’s no single “best” approach to refactoring, but here are common strategies - and when to use them:

1. Incremental Refactor (Recommended for Live Systems)

Refactor bit by bit, keeping the system functional at all times.

✅ Pros: Safe, gradual, easier to test
⚠️ Cons: Requires discipline and clear boundaries
✅ Best for: Actively used systems, critical codebases, or anything in production

2. Branch-based Refactor (When Changes Are Too Invasive)

Fork the code into a separate branch, refactor freely, and merge later.

✅ Pros: Total freedom to redesign
⚠️ Cons: Merge hell, risk of long-living branches, hard to keep in sync
✅ Best for: Isolated modules, internal tools, greenfield components

3. Strangler Fig Pattern (Great for Legacy Systems)

Wrap and slowly replace legacy logic, one endpoint or feature at a time.

✅ Pros: Legacy coexists with new code, safer evolution
⚠️ Cons: Requires architectural support (e.g., routing layers, boundaries)

🗂️ Control the Scope or You’ll Never Finish

One of the biggest risks in a refactor is the infinite scope creep. You touch one piece, which leads to another, and then another… and before you know it, it’s a rewrite.

Avoid this by:

• Defining clear boundaries - “Only refactor the email dispatch logic”
• Having non-negotiable out-of-scope rules - “Don’t rewrite the frontend now”
• Splitting the work into atomic, testable steps

💡 Tip: Track tasks in a checklist. Treat each step like a mini-feature.

🧱 Pick an Architecture or Pattern (Don’t Wing It)

Before you start moving code around, ask yourself: What kind of structure are we aiming for? Without a vision, you’ll likely make it different, not better.

Examples:

• Clean or Hexagonal architecture
• Adapter pattern to swap external services
• Strategy pattern to simplify logic by behavior
• Service layer for reusable business logic
• Ports and adapters to isolate frameworks

🧠 Refactor is not just renaming variables - it’s about redesigning how things work internally.

📦 Stabilize Interfaces (Create Contracts)

Even during a refactor, some parts of your system can’t change - external APIs, third-party expectations, or other modules still depending on them.

• Define stable interfaces or DTOs (data transfer objects)
• Keep method signatures consistent while you migrate under the hood
• Use adapters to convert legacy format to the new one temporarily

This makes it easier to refactor one part without breaking everything else.

🚩 Use Feature Flags

If your refactor affects a feature that’s already live, wrap the new version in a flag so you can:

• Test it in staging
• Gradually roll it out
• Roll back instantly if needed

This adds safety - especially when combined with CI/CD pipelines.

🧪 Define a Refactor Testing Strategy

You need different levels of tests to support your refactor:

• Unit tests for small modules
• Integration tests for connections between modules
• Regression tests to make sure nothing breaks
• (Optional) Snapshots or visual diffs for UIs

🔍 Also, use coverage tools to find untested danger zones before you touch them.

🛠️ Checklist Before the First Commit

Before writing any code:

• Refactor strategy selected (Incremental, Branch, Strangler)
• Scope clearly defined and limited
• Architectural target or pattern chosen
• Interfaces/contracts stabilized
• Feature flags planned (if needed)
• Tests prepared or planned
• Metrics defined (to validate results later)

📚 Series Index - Refactor Smart Today, Move Faster Tomorrow

A practical guide to refactoring without fear - from planning to validation.

1️⃣ Before You Touch a Line of Code

2️⃣ Plan Your Refactor Step by Step

3️⃣ Tools That Save You From Yourself

4️⃣ Refactoring Without Regret

5️⃣ After the Refactor: How to Know It Worked

✨ Bonus: 4 Lessons to Refactor Smarter (Not Harder)