As a developer, there’s always something to keep track of — codebases, services, servers, databases. The list never really ends, and sooner or later, something slips. Sometimes it’s minor. Sometimes it’s not.
Here are a few classic mistakes — the kind most of us have made at some point (myself included 😳) — and why they matter more than you might think.
Forgetting to renew your SSL certificate
It’s surprisingly easy to forget. Everything works fine — until it doesn’t.
An expired SSL certificate doesn’t just look bad. It breaks trust, triggers browser warnings, and in worst cases can expose users or services to risk.
It’s a bit like having a lock on your front door, but forgetting to replace the key after losing it.
And then there’s the classic scenario: you try to renew it, but something else is already bound to port 80. Nginx, Apache, a leftover container — suddenly the renewal process fails, and you don’t notice until the certificate has already expired.
The good news is that this is one of the easiest problems to automate. There are plenty of tools that monitor certificates and alert you before anything expires — use them.
Skipping backups — or never testing them
No one plans to lose their work.
But many systems are designed in a way that makes it possible.
Not having backups is bad. Having backups you’ve never tested is arguably worse.
It’s like backing up your phone photos but never checking if you can actually restore them.
Backups should be:
- taken regularly
- validated
- tested in real recovery scenarios
Because when something breaks, that’s not the moment you want surprises.
Not testing your code properly
Everyone knows testing is important.
But under time pressure, it’s often the first thing to go.
You might believe your code works perfectly. But without proper testing, you’re guessing.
And bugs discovered in production are always more expensive — in time, trust, and frustration.
It’s a bit like baking a cake without tasting it. You won’t know how it turned out until it’s too late.
A few simple principles go a long way:
- test the critical paths first
- assume things will break at the edges
- automate what you can
- and never trust a “quick fix” without verification
Because in the end, testing isn’t about proving your code works.
It’s about finding out where it doesn’t.
Cutting corners on security
Especially under pressure.
Security issues rarely show up immediately — but when they do, the impact can be significant.
Weak authentication, poor handling of sensitive data, missing controls — these things often creep in quietly.
A solid architecture process and proper risk assessment early on can prevent a lot of problems later.
Because leaving security as an afterthought is like leaving your windows open when you leave the house. You might be fine.
But you’re also inviting trouble.
And risk management isn’t something you do once. It’s continuous. Changes in systems, workflows or environments should trigger re-evaluation.
Not documenting your code
We’ve all been there.
Deadlines get tight. Delivery matters. Documentation gets skipped.
But code without documentation slows everything down:
- onboarding new developers
- debugging issues
- understanding intent
It’s like having a bookshelf full of books without titles or authors. You know something is there — but finding it becomes a problem.
And that problem gets expensive, fast.
Final thought
The list of things that can go wrong in software is practically endless. But most issues aren’t caused by complexity — they’re caused by small things being overlooked.
The kind of things that turn into “oops” and quietly become part of the system. And once they’re part of the system, they’re much harder to spot.