20 Essential Software Development Lessons Every Programmer Should Follow

Below are the software development lessons I have gathered after more than a decade as a programmer.

1. Start Small, Then Expand

Whether creating a new system or adding features to an existing one, I begin with the simplest possible version and gradually solve problems step by step, learning while developing and applying new knowledge to the solution.

I like John Gall’s saying: “Complex systems always evolve from simple systems.”

2. Change One Thing at a Time

When a test fails or a feature breaks, investigate a single issue per iteration. Resolve it fully before moving to the next, using short iterations and ensuring each change is isolated.

3. Add Logging and Error Handling Early

From the start, I add logs and error handling because they are essential for understanding what goes wrong and for handling exceptions as early as possible.

4. Every New Line of Code Must Run at Least Once

Before considering a feature complete, test it—preferably with automated tests—to guarantee that each new line actually executes.

5. Test Modules Before Full Integration

Testing individual modules first saves time and simplifies integration, as you can trust each component and more easily track integration issues.

6. Projects Take Longer Than Expected

Even when everything goes smoothly, estimating development time is hard; unexpected problems are common, echoing Hofstadter’s Law that tasks always take longer than we anticipate.

7. Understand Existing Code First

Before adding new functionality, study the current solution to avoid breaking existing features; reading and comprehending code is a necessary skill.

8. Read and Run the Code

Both reading the source and executing it are complementary ways to understand its purpose and behavior.

9. Bugs Are Inevitable

Don’t fall for the myth of “one‑click” development; accept that bugs will appear and design systems that allow quick troubleshooting and fixes.

10. Address Fault Reports

Every developer should spend time handling customer fault reports and fixing bugs, which deepens understanding of user intent and system design.

11. Reproduce the Problem

The first step in fixing a bug is to reproduce it, then verify that the fix eliminates the issue completely.

12. Fix Known Issues Before Searching for More

When multiple problems exist, resolve all known issues first, then look for any remaining hidden bugs.

13. Nothing Is a Coincidence

In testing and troubleshooting, changes are never accidental; unexpected side effects indicate deeper interactions that must be investigated.

14. Correlate Timestamps

Use event timestamps to trace problems—e.g., a system restart shortly after a 3000 ms request may point to a timer trigger.

15. Face‑to‑Face Communication Works Best

When discussing solutions, in‑person talks are more effective than video calls, phone calls, or email.

16. The Rubber‑Duck Method

Explain a tough problem to a colleague (or a rubber duck); the act of articulation often leads to sudden insight.

17. Ask Questions

Reading and running code helps, but consulting the original author or more knowledgeable peers can provide crucial context.

18. Share Credit

Give credit where it belongs—e.g., “Marcus came up with the idea”—instead of vague collective statements.

19. Try It Out

If you don’t understand a language feature, write a small program to experiment; the same applies to testing system behavior under edge conditions.

20. Sleep on the Problem

Working on a hard issue, then sleeping, can let the subconscious process it, often leading to solutions upon waking.

21. Don’t Fear Changing Jobs

Changing companies exposes you to new people, products, and cultures, which is valuable for growth.

22. Keep Learning

Continuously explore new programming languages, tools, books, and MOOCs; incremental learning eventually leads to a qualitative leap in ability.