Lessons from 25 Years of Software Engineering
I recently realized I’ve been writing code professionally for over 25 years. That’s a strange milestone to hit. Looking back, I wanted to share some of the most important lessons I’ve learned along the way.
1. Complexity is the Enemy
Early in my career, I thought good code meant clever code. I was wrong.
The best code I’ve written has been simple, boring, and obvious. Code that future-me (or anyone else) can understand at 2 AM when something’s broken.
Complexity is a tax on everything: maintenance, debugging, onboarding, and cognitive load.
Fight complexity at every turn. Choose the simplest solution that could possibly work, then refine from there.
2. Systems Thinking Matters More Than Code
As you gain experience, you realize that most problems aren’t really code problems. They’re systems problems.
Understanding how components interact, where bottlenecks form, and how failures cascade is more valuable than knowing every language feature or framework API.
3. Reading Code is a Skill
We spend far more time reading code than writing it, yet we rarely practice reading deliberately.
I’ve learned more from reading well-crafted codebases than from any tutorial or course. Find great projects, read them cover to cover, and ask yourself why every decision was made.
4. Documentation is a Gift to Your Future Self
I used to skip documentation. “The code is self-documenting,” I’d say.
That was foolish.
Good documentation isn’t about explaining what the code does—it’s about explaining why decisions were made, what alternatives were considered, and what constraints existed at the time.
5. Performance Matters, But Profile First
Premature optimization is real, but so is premature pessimization.
Make reasonable choices about data structures and algorithms from the start, but don’t obsess over micro-optimizations until you have data showing they matter.
Always profile. You’ll be surprised what’s actually slow.
6. Tests are Design Feedback
Tests aren’t just about catching bugs. They’re feedback on your design.
If something is hard to test, it’s probably poorly designed. Listen to that signal.
7. Shipping is a Skill
There’s a huge difference between “mostly done” and “shipped.” Learning to finish things, handle edge cases, polish rough edges, and actually deliver is its own skill.
Some of the best engineers I know aren’t the most technically brilliant—they’re just really good at shipping.
8. Tools Matter Less Than You Think
I’ve used dozens of languages, frameworks, and tools over the years. Most of them are fine.
What matters more:
- Clear thinking
- Communication skills
- Understanding the problem domain
- Knowing when to stop
Looking Forward
Even after 25 years, I’m still learning. The field moves fast, but the fundamentals remain surprisingly constant.
If you’re early in your career, don’t worry too much about picking the “right” technology. Focus on understanding principles, building things, and learning from every project.
The rest will follow.