Refactoring Legacy Code: Lessons from domesticating Almonds

What ancient agriculture can teach us about building better software

Cover image from Flickr (Vassilis)

I was deep into Guns, Germs, and Steel when I came across the chapter “How to Make an Almond.” I had picked up the book expecting grand historical narratives, but here was a lesson in patience, trial, and refinement—one that, unexpectedly, made me rethink software engineering.

Diamond describes how early humans tamed wild almond trees, which originally produced bitter, cyanide-laced nuts. By carefully selecting rare non-toxic mutations, they domesticated the almond into the snack we know today. This wasn’t a one-time breakthrough—it was a process of trial, error, and incremental refinement.

And that, it turns out, is exactly how good software gets built.

Selective Breeding and Incremental Refactoring

Early farmers didn’t create a perfect almond overnight. They found the occasional non-bitter nut and planted it, repeating this process over generations. The same principle applies in software engineering. Good systems aren’t built all at once; they evolve through selective improvement.

Refactoring is our form of selective breeding. When working with legacy code, we don’t rewrite everything from scratch—we identify parts that are working well and build upon them. Each clean-up, each optimisation, is like planting a better almond tree for future developers to harvest.

Working with Constraints: Nature vs. Legacy Code

Ancient farmers couldn’t just invent a new plant from thin air; they had to work within the genetic constraints of wild almonds. Similarly, engineers don’t always get to start with a greenfield project. We inherit constraints—technical debt, legacy codebases, backward compatibility needs.

Great engineers, like great farmers, succeed by understanding these constraints rather than fighting them. They find small, meaningful changes that steer the system toward a better state, rather than attempting a disruptive overhaul that could fail catastrophically.

The Power of Tiny, Meaningful Changes

The difference between a toxic wild almond and an edible one is a single genetic mutation. That one tiny change made all the difference. In software, small but thoughtful improvements—optimising a slow function, fixing an off-by-one error, making an API more intuitive—can have an outsized impact on system performance and usability.

In fact, some of the most impactful software innovations started as tiny changes. The hashtag on Twitter? Initially a user suggestion. Amazon’s one-click checkout? Just an incremental UI improvement. Like farmers selecting better almonds, engineers shape software through seemingly minor but cumulatively powerful adjustments.

Scaling Success: From Wild Plants to Global Software

Once early humans successfully domesticated almonds, they spread across civilisations, fuelling economies and diets. Similarly, well-engineered software isn’t just about fixing immediate problems—it’s about creating scalable solutions that can be replicated and adapted across different contexts.

Good API design, modular architectures, reusable libraries—these are our domesticated almonds. The best software isn’t just functional; it’s something that others can easily build upon. It scales because it’s been thoughtfully cultivated from the ground up.

The Long Game: Engineering as Cultivation

The lesson from “How to Make an Almond” is that transformation doesn’t happen overnight. Whether it’s agriculture or software, success is an accumulation of small, deliberate improvements. We don’t need to create perfection in a single sprint—we just need to select the right mutations, prune the bad ones, and keep planting the seeds of better code.

So next time you’re refactoring a messy or legacy codebase, think of the ancient farmer selecting almonds on the hillsides of the Fertile Crescent. And remember: engineering, like farming, is about patience, persistence, and the long game.