Writing Clean, Maintainable Code: Principles That Stand the Test of Time
At TCCB Solutions, we've inherited our fair share of codebases. Some are a joy to work with; others feel like archaeology. The difference rarely comes down to clever frameworks or cutting-edge tools — it comes down to discipline. Clean code isn't about elegance for its own sake. It's about reducing the cost of change, because the code we write today will be read, debugged, and extended for years.
Here are the principles we keep coming back to, project after project.
Name Things Honestly
The single most impactful habit we've adopted is choosing names that describe intent, not implementation. A variable called d tells us nothing. elapsedDays tells us everything.
// Hard to read
function calc(u, d) {
return u.r * d * 0.85;
}
// Self-documenting
function calculateDiscountedTotal(user, days) {
const LOYALTY_DISCOUNT = 0.85;
return user.dailyRate * days * LOYALTY_DISCOUNT;
}Good names eliminate the need for most comments. If you find yourself writing a comment to explain what a variable holds, rename the variable instead.
Functions Should Do One Thing
We aim for functions that fit on a single screen and have a single, clear responsibility. When a function starts juggling validation, database calls, formatting, and notifications, it becomes nearly impossible to test or reuse.
A useful heuristic: if you can't summarize what a function does without using the word "and," it's doing too much. Break it apart.
Optimize for the Reader
Code is read far more often than it's written. We optimize for the developer who arrives six months from now with no context — often, that developer is us.
- Prefer clarity over cleverness. A three-line loop beats a dense one-liner nobody can parse.
- Keep related code close together. Don't make readers jump across five files to follow one flow.
- Make the common path obvious. Edge cases and error handling should be visually distinct from the happy path.
Embrace Boring Consistency
Consistent code is predictable code. We follow conventions even when we'd personally prefer something different, because consistency across a codebase reduces cognitive load more than any individual stylistic preference improves it.
This applies to formatting (use a formatter — prettier, black, gofmt — and stop debating it), file structure, naming conventions, and error handling patterns. Pick a style, document it, and stick to it.
Don't Repeat Yourself — But Don't Over-Abstract
The DRY principle is one of the most misapplied ideas in our field. Yes, duplicated logic is a maintenance burden. But premature abstraction is worse: it locks in assumptions before you understand the problem.
Our rule of thumb: see a pattern three times before extracting it. Two similar pieces of code might be coincidence; three is a signal. Until then, a little duplication is cheaper than the wrong abstraction.
Handle Errors Where You Can Act on Them
Wrapping every operation in a try/catch and logging "something went wrong" is not error handling — it's noise. We let errors propagate to the layer that actually knows what to do about them, and we make sure errors carry enough context to be useful.
// Useless
catch (e) {
console.log('error');
}
// Useful
catch (error) {
throw new PaymentError(
`Failed to charge user ${userId} for order ${orderId}`,
{ cause: error }
);
}Write Tests That Document Behavior
Good tests are executable documentation. When someone reads a test file, they should understand what the system is supposed to do. We name tests as sentences: it('refunds the full amount when cancelled within 24 hours') beats testRefund1() every time.
Tests also act as a safety net for future change. The codebases that age well are the ones where developers feel safe to refactor, and that safety comes from tests.
Leave It Better Than You Found It
The boy scout rule. Every time we touch a file, we look for one small improvement: a clearer variable name, a deleted dead branch, an extracted constant. Codebases don't decay in dramatic ways — they decay one shortcut at a time. They improve the same way.
The Long View
Clean code isn't about following rules. It's about respecting the people who'll work with your code next — including your future self. The principles above haven't changed much in decades, and they probably won't change much in the decades ahead.
If you're building something and want a team that takes maintainability seriously from day one, we'd love to hear about your project.