How do you teach SOLID principles to a development team?

Teaching SOLID effectively requires moving beyond definitions to recognition and practice. Effective approaches: (1) Code smell → principle mapping — start with identifying smells in the team's own codebase (God Classes, long methods, hard-to-test code) and connect each to the SOLID principle it violates. Learning from real pain is more memorable than abstract examples. (2) Before/after refactoring exercises — show a violating codebase, have developers refactor it, then discuss trade-offs. (3) Coding katas — exercises like Bowling Game, Roman Numerals, or Gilded Rose Refactoring Kata build SOLID muscle memory. (4) Pair programming and code review — real-time SOLID guidance during peer review normalizes the vocabulary and patterns. (5) Gradual introduction — start with SRP (most intuitive), then OCP, and build to DIP (most abstract). (6) Anti-pattern recognition — teams learn faster by seeing what NOT to do. Document SOLID decisions in architecture decision records (ADRs) to create institutional memory.