There’s a terminal somewhere still running software written in 1987. Not as a museum piece — as a live production system. Someone’s payroll depends on it.
The Weight of Old Code
Every line of code is a bet on the future. When you write if user.admin?, you’re betting that the concept of “admin” will still make sense when someone reads this in ten years. Sometimes you win. Often you don’t.
The machines don’t forget. That’s their gift and their curse. Every assumption you bake in is preserved in amber.
What Durability Actually Means
Durability in software isn’t about writing code that doesn’t change — it’s about writing code that can change without collapsing everything around it.
# The most durable systems I've seen have one thing in common:
# they're boring. Deliberately, stubbornly boring.
grep -r "clever" ./src | wc -l # should be 0
Clever code is a liability. The cleverness is never in the running — it’s in the reading, six months later, at 2am, when something is on fire.
A Heuristic
If you can’t explain what a piece of code does to someone unfamiliar with the system in under two minutes, it will eventually become unmaintainable.
This isn’t about simplicity for its own sake. It’s about the time cost of comprehension compounding across every future reader.
Write for the reader who will be tired, stressed, and under pressure. Write for 3am.
The machines we build are artifacts. They carry intent long after the intent fades. Build accordingly.