Beyond DRY: Embracing Strategic Duplication for Better Code

• Sciaria
• Development
• Nov 09, 2025
• 0 Comments

The DRY (Don't Repeat Yourself) principle is a cornerstone of good software development. It champions the elimination of redundant code, promising easier maintenance, fewer bugs, and greater consistency. For good reason, it's often one of the first lessons taught to aspiring developers. However, like any principle, taking DRY to an absolute extreme can sometimes lead to more harm than good, inadvertently creating complex, tightly coupled, and ultimately harder-to-manage systems. It's time to explore the often-overlooked virtue of strategic duplication.

While repetitive code can undoubtedly be a smell, not all duplication is created equal. Over-zealous application of DRY can lead to premature abstraction, where developers create intricate layers of shared code before the true commonalities and future evolution paths are clear. This can result in 'false DRY' – an abstraction that binds two or more disparate concepts together, forcing them to change in lockstep even when their business logic or context should allow them to evolve independently. Such abstractions become brittle, difficult to refactor, and can significantly increase the cognitive load for new team members trying to understand the system.

So, when might duplicating code strategically be a wise choice? Consider situations where code, though appearing similar, lives in different bounded contexts or is part of separate microservices. Forcing a shared library between these contexts might seem like a DRY win, but it introduces a tight coupling. A change in the shared library, even if only relevant to one service, could inadvertently impact others, leading to complex deployment pipelines and increased risk. Instead, a measured amount of duplication can promote independence, allowing each service or context to own its code, simplifying deployment, and fostering greater autonomy for development teams.

Furthermore, sometimes a bit of duplication can actually improve clarity and readability. An overly abstract solution designed to satisfy strict DRY requirements might involve complex inheritance hierarchies, multiple levels of indirection, or generic functions with numerous parameters. In contrast, a slightly duplicated, but contextually specific, piece of code can be much easier to understand, debug, and modify. The famous "Rule of Three" suggests that you should only abstract code once you've written it three times, allowing a clearer pattern to emerge naturally rather than forcing one prematurely.

Ultimately, embracing strategic duplication isn't about abandoning the DRY principle; it's about applying it with wisdom and discernment. It's about recognizing that code architecture is a balancing act. While redundancy can be costly, so too can premature or overly complex abstraction. Developers should always strive for maintainable, clear, and flexible code, and sometimes, a little thoughtful repetition, rather than rigid adherence to a dogma, is the most virtuous path forward.