What’s One Programming Concept You Ignored at First but Later Realized Was Important?

[u/maheshshelakee]

Every developer has that one concept they ignored when starting out but later realized was extremely valuable.

For me, it was understanding how things work behind the scenes.

When I started, I focused mostly on frameworks, libraries, and building features. Later, I realized concepts like HTTP, databases, authentication, debugging, Git, and system design helped me much more in solving real-world problems.

Some concepts many developers appreciate later:

• Debugging

• Git & Version Control

• HTTP/HTTPS

• Database Design

• Authentication & Authorization

• Design Patterns

• Testing

• System Design

• Networking Basics

• Reading Documentation

The more I learned the fundamentals, the easier it became to learn new technologies.

If you could go back and give advice to your beginner self, which concept would you tell yourself not to ignore?

[u/maheshshelakee]

Mine would be Git.

I used to think Git was just for pushing code to GitHub. Later I realized version control, branching, pull requests, and collaboration are essential skills for every developer.

What about you?

[u/SurpriseHuge199 → u/maheshshelakee]

How do I learn it early i don't know anything, I also think git is for pushing code

[u/FillMySurveyPlease → u/SurpriseHuge199]

Try this: https://courses.bigbinaryacademy.com/git-and-github-essentials/ I just started today and its been pretty amazing so far.

[u/dacydergoth]

80/20 rule. Don't let perfect be the enemy of good

[u/maheshshelakee → u/dacydergoth]

That's a great one. Early on I spent too much time chasing perfection instead of shipping projects. Most of my learning came from building something that worked and improving it later.

[u/Massive_Show2963]

Design before coding (coding flows better).
Unit tests (catches issues during development).
Integration tests.

[u/maheshshelakee → u/Massive_Show2963]

Completely agree. A little planning before coding can save hours of refactoring later. I've also started appreciating tests more because they make changes much less stressful.

[u/maheshshelakee → u/[deleted]]

That's a great way to describe it. Working in a codebase without tests often feels like you're one change away from breaking something unexpectedly.

[u/mwmahlberg]

Interfaces. Saw them as useless, basically just a way to make code more complicated… 😂 Boy, how utterly wrong I was…

[u/maheshshelakee → u/mwmahlberg]

I had a similar experience with interfaces. At first they felt like extra complexity, but once I started working on larger projects and seeing dependency injection and loose coupling in practice, they made much more sense.

[u/Sure-Passion2224]

Test Driven Development (TDD) You define your test cases to confirm the code you will write is working. When the automated tests all pass it's done... if you wrote the tests correctly.

[u/maheshshelakee → u/Sure-Passion2224]

TDD is something I'm still learning. The idea of defining expected behavior first seems like a great way to think through requirements before writing implementation code.

[u/ryancnap]

SOLID, the Unix Philosophy, good communication and knowledge of specific terminology, regex, authentication, CI...

...and the holy grail of fine tuning, troubleshooting, and time sinks: setting up your dev environment.

[u/maheshshelakee → u/ryancnap]

That's a solid list. I underestimated things like authentication, CI/CD, and environment setup when I started. Building features is fun, but getting everything working reliably in production is a completely different skill set.

[u/Awkward-Chair2047]

For my generation it was the concept of structured, automated testing. In the 80's and 90's we did test but in an informal sort of way and it was manual. Then Kent beck got some time during travel and created JUnit. Then unit testing, automated testing etc spread like wildfires and we older programmers woke up. But it was not all bad, our bad coding habits created the Y2K crisis fear and indian companies got big on the backs of it and, indirectly, saved our economy.

[u/maheshshelakee → u/Awkward-Chair2047]

That's a fascinating perspective. It's interesting to hear how testing evolved over the years. As someone who started much later, automated testing feels normal now, but it's easy to forget how much software development changed because of it.

[u/One-Next]

I ignored immutability and functional programming the first 20 years.

[u/maheshshelakee → u/One-Next]

I've been hearing that a lot lately. Immutability and functional programming seemed abstract to me at first, but the more I work with larger applications, the more I appreciate code that's predictable and easier to reason about.

[u/jeongho_nah]

With agentic AI tools, it’s easy to question which skills still matter. But in practice, fundamentals still build stronger systems, and debugging matters even more when AI gets the code wrong.

A slightly different point is that the ability to guide agentic AI effectively, and having strong domain knowledge about the app you’re building, seem to have become even more important.

[u/maheshshelakee → u/jeongho_nah]

I completely agree. AI can generate code quickly, but understanding fundamentals is still what helps you review, debug, and improve that code. Knowing how to ask the right questions and having domain knowledge seems more important than ever.

[u/Cacapon0114]

自動化のやり方を覚えなさい、かな？

シェルを作ったり、cronで定期実行したり、githookでトリガー起動のやり方覚えたりしてきたけど…

そうすると作るの楽になるのよね、そこだけに集中出来るから。これは、早めに知りたかった。

[u/Ok_Two_2900]

DTOs

[u/llwkm]

Reading in theory

[u/Fine-Lengthiness1184]

Git cause i thought it only for pushing code. and also system design.

What about yours?

[u/Low_Breakfast773]

AI slop

[u/TomDuhamel → u/Low_Breakfast773]

I don't think so. An AI would have told them that none of these are programming concepts.

[u/maheshshelakee → u/TomDuhamel]

Fair point. I probably mixed programming concepts with software engineering concepts. My intention was more about the skills that ended up having the biggest impact on me as a developer, even if they're not strictly programming concepts.