Refactoring vs. Replacing Legacy Code: What’s Right for Your Business?
Legacy code refers to software that is typically still running in production, despite being written years ago. In fact, any existing code is considered legacy. For example, your company might be in phase four (PH4) of a system written six years ago. While this code plays a crucial role, it often becomes a bottleneck as the system grows outdated, leading to inefficiencies.
An old system doesn’t have to meet any particular threshold to be considered legacy—it’s simply anything old that is being replaced or updated. However, managing legacy code can introduce complexities into day-to-day operations.
Why Is Legacy Code So Challenging?
Legacy code often comes with a host of issues that slow down progress:
- Complexity and Confusion
Over time, legacy code can become difficult to read and understand. Since it's likely written without the structure and clarity of modern practices, even small changes can create significant problems elsewhere in the system. What might seem like a minor update could lead to larger, unexpected issues that take time and effort to resolve. - Outdated Packages and Documentation
The libraries and packages used in legacy code are often outdated, meaning the documentation might not be comprehensive or readily available. This makes investigating and fixing issues much more time-consuming. Additionally, developers may struggle with older programming languages or practices that the current team isn’t proficient in, leading to further delays.
- Testing and Risk One of the most significant challenges with legacy code is testing. If there are no existing tests, making changes becomes risky. Adding new features or fixing bugs without adequate testing can lead to failures, especially when tight deadlines push teams to avoid quick fixes. Lack of testing leads to risky updates, and rushing through them can compromise the stability of the entire system.
What Does This Mean for Your Business?
When dealing with legacy code, you generally have two options:
Refactoring
Refactoring involves improving the existing code without changing the user experience. It entails cleaning up the code to make it more maintainable and efficient while keeping the system stable. While it’s a long-term investment, refactoring can pay off quickly by improving code quality without disrupting operations.
During refactoring:
- Testing is crucial to ensure stability after changes.
- Clean coding principles should be applied to maintain readability and structure.
- It’s important to identify potential pitfalls that could affect the system’s structure.
Replacing Legacy Code
Sometimes, replacing the legacy system entirely is the best choice, especially if the old code is too costly or risky to maintain. This decision depends on the needs of the business, the complexity of the legacy system, and the cost of engineers’ time and resources. While modernizing code can lead to long-term savings, the process may require a large upfront investment of time and resources. Additionally, cloud-based solutions can reduce costs compared to on-premises infrastructure, but they may introduce concerns over data security and vendor lock-in.
Why Keep Legacy Code?
Despite its challenges, there are reasons why businesses often hold on to legacy code:
- Cost Management
The cost of replacing legacy code or implementing new systems can be high. Legacy systems, though inefficient, often continue to function without major issues, making the upfront cost of replacement harder to justify.
Additionally, the cost of engineers' time and the complexity of managing an older system might still be cheaper than a full overhaul, especially if the code is running on-premises versus moving to the cloud.
- Situational Considerations
New features can push for a rethink of current solutions, but legacy code may still fit specific business needs. The decision to upgrade or replace legacy systems should be based on the long-term vision of the company and the resources available for transition.
- Documentation and Ongoing Maintenance
One overlooked aspect of legacy code is documentation. In many cases, older systems lack comprehensive, up-to-date documentation. Ensuring that codebases are well-documented and that the documentation is maintained as a "living document" can significantly ease the burden of working with legacy systems. This helps the engineering team pull in libraries or packages when needed without having to rewrite existing solutions.
If your system lacks testing, writing tests for the most critical pieces is the first step. This allows developers to work confidently, knowing that their updates won’t cause unintended issues.
Refactoring: A Long-Term Strategy
Refactoring isn’t a quick fix. It’s a long-term strategy that helps create more maintainable and efficient code. By taking the time to refactor, you give your engineering team more freedom to grow, innovate, and add new features without the constant fear of breaking the system.