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.

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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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.

Systems thinking matters.

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.