Legacy code can be a major bottleneck for Agile teams. Often riddled with outdated patterns, limited test coverage, and tangled dependencies, it slows delivery and introduces technical debt. However, Scrum’s iterative and incremental approach provides a disciplined framework to chip away at this complexity without derailing delivery goals.

This post explores practical Scrum-based strategies for refactoring legacy code, helping teams deliver value continuously while improving code maintainability.

Why Legacy Code Needs Refactoring

Legacy systems typically evolved without structured refactoring. They might lack unit tests, contain obsolete technologies, and resist change due to poor design. These issues result in:

• Frequent defects and regressions
• Difficulty in onboarding new developers
• Slowed-down sprint velocity
• Risky deployments and rollbacks

To mitigate these problems, development teams must invest in ongoing refactoring. Scrum provides the rhythm and structure to do this gradually without losing sight of sprint goals.

Embed Refactoring into Scrum Workflow

Scrum doesn't dictate engineering practices, but it creates the cadence to build quality iteratively. Here’s how you can embed refactoring efforts within a Scrum team:

1. Include Refactoring in the Definition of Done (DoD)

Update the team’s Definition of Done to include code cleanliness, removal of duplication, and improved readability. If refactoring becomes a shared accountability in the DoD, it won’t be left as an afterthought.

This not only aligns with certified scrum master training principles but also ensures a sustainable pace of development.

2. Refactor Opportunistically During Sprint Tasks

Refactor while implementing new features or fixing bugs. Don’t go looking for refactoring opportunities—make it a habit to clean as you go. For instance, when modifying a class, take time to apply the Single Responsibility Principle or eliminate duplication in the methods.

3. Break Down Refactoring into Sub-Tasks

Legacy refactoring isn’t a one-off task. Use sub-tasks in the sprint backlog to scope changes realistically. A Product Backlog Item (PBI) like “Refactor data access layer for product module” can be decomposed into:

• Add unit tests for current logic
• Extract database access to repository pattern
• Remove dead code paths

4. Leverage Technical Spikes

Use spikes to investigate refactoring strategies—e.g., analyzing the impact of introducing dependency injection. Document learnings and use them to create technical stories. This helps avoid guesswork in future sprints.

5. Make Technical Debt Visible on the Product Backlog

Work with the Product Owner to include refactoring items in the backlog. Label them as “tech debt” so they don’t get deprioritized indefinitely. Over time, the team can estimate these tasks and prioritize them based on risk, value, or urgency.

6. Use Sprint Retrospectives to Push for Code Quality

Retrospectives are ideal for surfacing code pain points. If multiple developers struggle with the same class or module, that’s a clear sign it needs refactoring. The Scrum Master can help capture these insights and facilitate backlog items or DoD updates.

If you're pursuing SAFe Scrum Master certification, you'll learn how to scale such quality improvements across multiple teams.

Balancing Refactoring with Sprint Commitments

One challenge teams face is balancing feature delivery and code improvement. Here’s how you can maintain this balance:

Strategy	Benefit
Timebox Refactoring Sub-Tasks	Prevents gold-plating; keeps effort visible
Use Story Points for Refactor Items	Helps in velocity tracking and sprint planning
Agree on a Refactoring Budget per Sprint	Ensures sustainable investment in tech debt
Track Refactoring KPIs	Gives visibility into improvements

Test Coverage: A Prerequisite for Safe Refactoring

You can’t refactor safely without sufficient test coverage. Teams must aim for high unit test coverage before touching core modules. Practices like test pyramids help balance unit, integration, and end-to-end tests.

Additionally, modern CI pipelines with automated regression testing act as safety nets during refactoring. For deeper Scrum alignment, integrate testing into every sprint and inspect it during the csm certification training sessions.

Tools and Techniques That Support Scrum-Based Refactoring

• Static Code Analyzers: Tools like SonarQube surface code smells, cyclomatic complexity, and duplication.
• Mutation Testing: Tools like Pitest (for Java) help verify your test suite’s robustness.
• Version Control Best Practices: Use feature toggles and trunk-based development to decouple legacy cleanup from active feature delivery.

Collaborate Closely with the Product Owner

The Product Owner must understand the value of a maintainable codebase. Use sprint reviews to demo not just features, but also before-and-after snapshots of code improvements. This reinforces the importance of long-term technical health.

When to Schedule Dedicated Refactoring Sprints

While not always needed, dedicated refactoring sprints can help tackle systemic legacy issues—like migrating from a monolith to microservices or introducing a new ORM. Use them sparingly and follow them with normal feature-focused sprints to maintain business momentum.

Key Takeaways for Scrum Teams

• Make refactoring a part of the team’s culture, not a one-off initiative
• Use Scrum ceremonies to surface and act on legacy pain points
• Align Product Owner expectations to prioritize technical health
• Automate testing to create safety nets for change

Conclusion

Legacy code can be transformed gradually through a disciplined, Scrum-based approach. By embedding refactoring into your sprints, involving the Product Owner, and tracking progress using structured backlog items, teams can reduce technical debt without sacrificing velocity.

Interested in helping your team drive quality? Explore csm training and SAFe Scrum Master Training to deepen your Agile expertise and gain the tools to lead effective refactoring initiatives.

 

Also read - Optimizing Database Changes and Migrations in Sprint Cycles

Also see - Integrating Load Testing into Definition of Done