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Lessons Learned Over Years in Development - Mistakes and Successes

Performance

Throughout my career as a developer, I have made mistakes and learned valuable lessons that have changed the way I work. At first, I thought the most important thing was to write code that worked as quickly as possible, but over time, I discovered that quality, communication, and planning are just as essential.

In this article, I will share some common mistakes I have made (or seen others make) and the lessons I have learned from them.

1. Clean and Maintainable Code: More Important Than It Seems

Mistake:

When I started programming, my priority was making the code work, regardless of its structure. This led me to write code that was hard to read, with poorly named variables, huge functions, and chaotic organization. At first, it didn’t seem like a problem because I understood what I had written, but over time, maintaining and scaling those projects became a nightmare.

Lesson:

Code maintainability is key—not just for me but for anyone who has to work with it in the future. Applying principles like SOLID, DRY (Don’t Repeat Yourself), and KISS (Keep It Simple, Stupid) helps write clearer and more modular code.

Real Example:

In an old project, I created a function with more than 300 lines that handled all the business logic in a single block of code. Months later, when I needed to make changes, it took me hours to understand what it actually did. That’s when I learned the importance of breaking logic into smaller, more understandable functions.

Practical Advice:

Always ask yourself: “If someone else had to understand this code without asking me anything, could they do it in just a few minutes?” If the answer is no, it’s time to refactor.

2. The Importance of Writing Tests (and How I Avoided It at First)

Mistake:

For a long time, I avoided writing tests because I thought they were a waste of time. “If I’ve already tested the code manually and it works, why do I need tests?” I thought. Then, a production bug changed my mind.

Lesson:

Tests not only prevent production errors but also allow you to refactor with confidence. A good set of automated tests saves a lot of time in the long run.

Real Example:

In a project, I made changes to a function without realizing I was breaking another part of the application. There were no tests to alert me to the problem, and the bug went live, affecting users. Since then, I always include unit, integration, and/or end-to-end tests as needed.

Practical Advice: • Implement TDD (Test-Driven Development) if possible. • Use tools like Jest for React or JUnit for Java. • Prioritize writing tests for the system’s critical parts.

3. It’s Not Just About Code: Communication Is Key

Mistake:

As a developer, I used to focus on writing code without paying attention to communication with the team or clients. I assumed requirements were clear and that there was no need to ask too many questions.

Lesson:

Lack of communication leads to misunderstandings, incorrect requirements, and rework. Talking to the team, documenting decisions, and ensuring everyone is aligned prevents future problems.

Real Example:

In one project, I misinterpreted a requirement because I didn’t clarify certain details with the client. I spent weeks developing a feature that wasn’t what they actually needed. I learned that it’s always better to ask questions and validate before starting to code.

Practical Advice:

  • Use agile methodologies like Scrum or Kanban to improve team communication.
  • Learn to ask key questions to understand client requirements.
  • Document important decisions to avoid future confusion.

4. Architecture Matters More Than It Seems

Mistake:

In my early projects, architecture wasn’t a priority. I added features without a clear structure, resulting in messy and hard-to-scale code.

Lesson:

Choosing the right architecture from the start makes the application more scalable and easier to maintain. Thinking about modularity, separation of concerns, and appropriate design patterns is fundamental.

Real Example:

I worked on a project where the entire backend was in a single massive file with no separation of layers (controller, service, repository). Over time, the code became unmanageable. I had to refactor the entire structure, applying the MVC (Model-View-Controller) pattern, which made the code much more organized and easier to extend.

Practical Advice:

  • Use architectural patterns like MVC, Hexagonal Architecture, or Clean Architecture, depending on the type of application.
  • Divide code into independent modules to facilitate maintenance.
  • Don’t hesitate to refactor if the initial architecture starts to become a problem.

5. Continuous Learning Is Mandatory

Mistake:

There were times when I felt comfortable with what I knew and stopped learning new technologies or methodologies. But in the development world, staying stagnant means falling behind.

Lesson:

Continuous learning is essential. Technology evolves, and staying updated on new tools and paradigms is crucial to remaining a valuable professional.

Real Example:

When I started with React, I initially resisted using Hooks because I was used to class components. After seeing their potential and simplifying code with useState and useEffect, I realized that updating skills is not just necessary but actually makes life easier.

Practical Advice:

  • Dedicate time each week to learning something new (a language, framework, or concept).
  • Follow blogs, online courses, and developer communities.
  • Don’t be afraid to try new tools, even if they feel uncomfortable at first.

Conclusion

Over the years, I have learned that being a good developer is not just about writing code that works but about writing clean code, maintaining good communication, choosing the right architecture, and never stopping learning.

If I had to summarize my lessons in one sentence, it would be: “Code with the future in mind—yours and the people who will work with your code.”

I hope these reflections are useful to you. If you have had similar experiences, I would love to hear them in the comments. What mistakes and lessons have you learned on your journey as a developer?