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Posted 17 days ago · 25,666 reads

Legacy code is called legacy for a reason. It works. It's been tested in production. It's often the most reliable code in your system, even if it doesn't follow modern conventions.

APIs are contracts. Once you publish one, changing it becomes expensive for everyone who depends on it. The cost of breaking changes compounds over time, which is why the boring, conservative choice is usually the right one.

Constraints breed elegance.

Legacy code is called legacy for a reason. It works. It's been tested in production. It's often the most reliable code in your system, even if it doesn't follow modern conventions.

Type systems don't prevent bugs—they just catch certain categories of bugs earlier. The real benefit is the documentation they provide about what a function is supposed to do.

Legacy code is called legacy for a reason. It works. It's been tested in production. It's often the most reliable code in your system, even if it doesn't follow modern conventions.

Legacy code is called legacy for a reason. It works. It's been tested in production. It's often the most reliable code in your system, even if it doesn't follow modern conventions.

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Most of the code we write is not rocket science. It's ordinary business logic, wrapped in layers of frameworks and abstractions. Sometimes the simplest implementation is the best.

The best code is often the code you don't write.

The most important insight I've had in the last few years is that constraints are a feature, not a bug. When you have unlimited resources, you can solve any problem in a hundred different ways. When you have constraints—limited memory, limited time, limited developers—you're forced to think more clearly.

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