Clean Code, Refactoring, and Maintainability Questions

Writing code that other people can read, change, and keep alive over time: naming, function and module decomposition, avoiding duplication, readability, disciplined use of language idioms and design patterns, and recognizing code smells, extending into working effectively in large, aging, or unfamiliar codebases through safe incremental change, refactoring under test coverage, and managing technical debt. Covers both authoring professional-grade code beyond mere correctness and improving code you cannot rewrite without breaking it. Spans the coding-round quality signal and the seniority signal of leaving a codebase healthier than you found it.