Why Programmers Refactor Code and How to Do It Effectively

When developers encounter tangled code, massive functions, or slow legacy systems, they face a choice: tolerate the mess or refactor it. The "three‑time rule" describes how tolerance erodes after repeated encounters, eventually forcing a refactor.

Typical scenarios include developers changing hundreds of files for a small feature, causing testers to repeat regression work, and product managers questioning the value of refactoring when no visible user benefit appears.

In one case, a core system with poor initial design grew into a monolithic, tightly‑coupled codebase that frequently caused business outages. The team decided to split the system into smaller, single‑purpose subsystems to reduce coupling, treating the effort as a top quarterly priority.

However, the refactoring process turned into a maze: while the old system was still being modified, new features were added to both the legacy and the refactored branches, leading to chaotic merges, delayed schedules, and extensive re‑work. The launch slipped from September to June of the following year, exhausting the team and causing turnover.

The experience highlighted three major mistakes: mixing refactoring with feature development, lacking a clear project plan, and not integrating testing into the refactoring workflow.

To refactor responsibly, the article recommends three practices:

Separate the two hats: keep refactoring (improving code design without changing functionality) distinct from adding new features, allowing existing tests to validate changes.

Adopt a "small‑step, fast‑run" strategy: focus on one problem at a time, making tiny, incremental improvements that are quick to implement and verify.

Use test‑driven development: embed testing into each refactoring step, ensuring code quality continuously rather than relying on a massive testing effort after the fact.

By following these principles, teams can reduce risk, maintain project momentum, and produce code that is both machine‑readable and human‑readable, aligning with the wisdom from the book "Refactoring" that true excellence lies in writing code that humans can easily understand.

Source: https://mp.weixin.qq.com/s/pD7vCGW9iX3C0mlNl9skww