DRY and Code Reuse Principles

Tool-agnostic, language-agnostic development principles for understanding DRY, code reuse, and abstraction strategies.

I need to...

I need to...	Guide
Understand what DRY actually means	DRY Overview
Know when duplication is acceptable	Four Types of Duplication
Choose between DRY, WET, or AHA approaches	DRY vs WET vs AHA
Identify code duplication in my project	Code Duplication
Ensure single source of truth for business rules	Knowledge Duplication
Learn abstraction strategies	Abstraction Strategies
Know when it's safe to abstract	Rule of Three
Apply DRY to configuration	DRY in Configuration
Apply DRY to documentation	DRY in Documentation
Apply DRY to tests	DRY in Testing
Apply DRY across system boundaries	DRY Across Boundaries
Avoid over-abstraction	Over-DRY Anti-Patterns
Get a practical decision framework	Best Practices Decision Framework
Detect duplication in my codebase	Code Smells and Detection
Find authoritative sources	Code Reference Map