In software development, we often talk about writing “efficient” code – but what does that really mean? For some, it’s about speed and low resource usage; for others, it’s about clarity and flexibility. In truth, it’s rarely a matter of one or the other. The best code is both optimised and understandable – and the real skill lies in finding the balance between the two.

When Optimisation Becomes a Trap

It can be tempting to optimise everything. To remove every redundant calculation, use low-level functions, and squeeze every last drop of performance from the hardware. But over-optimisation can quickly make code difficult to read and even harder to maintain.

A common example is when developers “improve” a function that runs only occasionally, but make it so complex that no one dares to touch it later. The result? A fast but fragile solution that costs more time in the long run than it ever saved.

As computer scientist Donald Knuth famously said, “Premature optimisation is the root of all evil.” The point is that you should only optimise once you know where the real bottlenecks are.

Readability as an Investment

Readable code isn’t just nicer to look at – it’s an investment in the future. When you or your colleagues return to a project months later, it’s crucial that the code still makes sense. The goal is to make the intention clear: not just how something is done, but why.

Use meaningful names, break complex functions into smaller parts, and document decisions that aren’t obvious. This makes it easier to fix bugs, add features, and onboard new developers. A codebase that’s easy to understand is also easier to optimise later – because people feel confident making changes.

Measure Before You Optimise

Before you start optimising, you need to know what you’re optimising for. Is it speed, memory usage, response time, or energy efficiency? Without concrete measurements, you risk spending time improving something that isn’t actually a problem.

Profiling tools can help identify where your program spends most of its time. Often, you’ll find that 80% of the runtime is spent in 20% of the code. By focusing your efforts there, you can achieve significant improvements without compromising the rest of the system.

Know Your Context and Your Audience

A crucial part of balance is understanding context. A prototype built to demonstrate an idea doesn’t need to be perfectly optimised. A real-time control system, on the other hand, demands maximum performance. The same goes for the difference between an internal tool and a public API that must scale to thousands of users.

Ask yourself: Who will read and maintain this code? How long is it expected to live? What are the performance requirements? The answers will guide you towards the right trade-offs.

Small Steps Towards Better Balance

Finding the balance between performance and maintainability requires awareness and discipline. Here are some practical tips:

• Start simple. Write a clear, working solution first. Optimise only where it truly matters.
• Use tests. Good test coverage gives you the confidence to optimise without breaking functionality.
• Document optimisations. Explain why you chose a particular approach, especially if it’s not the obvious one.
• Rely on data. Use measurements and benchmarks to guide decisions – not gut feeling.
• Share knowledge. Conduct code reviews so that more people understand the critical parts of the system.

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The Maintainable Optimisation

The best optimisation is the one that doesn’t come at the cost of understanding. It’s not about choosing between fast and clean code, but about writing fast code that’s still clean enough for others to work with.

When you achieve that, you don’t just get a faster program – you get a healthier project. A project where developers feel confident improving, extending, and experimenting because they understand what’s going on. And that, ultimately, is the most sustainable form of optimisation.