software-development

Layer separation enforces putting business logic in model methods rather than controllers. Move operations like Order.confirm() into the model; controllers call these methods and remain thin. This reduces duplication, improves testability, and makes maintenance easier by centralizing logic where it belongs.

DRY (Don't Repeat Yourself) violations occur when the same logic appears in multiple places. Extract repeated patterns into reusable model methods or utility functions. This reduces bugs, simplifies updates, and improves readability by ensuring each piece of logic exists in exactly one location.

Try/catch blocks should handle genuinely exceptional conditions, not control flow. Avoid wrapping code defensively or catching exceptions you don't actually handle. Use them purposefully for specific error recovery; unnecessary blocks hide real issues and make code harder to follow.

Common anti-patterns include fat controllers, unused variables, unclear exception handling, and mixed concerns across layers. Clean-code principles enforce layer boundaries, defensive coding practices, and explicit exception handling. Regular refactoring to these standards reduces bugs and technical debt.

Structure workflows with clear separation: models hold business logic, controllers handle requests and responses, and each layer has a single responsibility. This architecture keeps code testable, reduces coupling, and makes it easier to locate and modify functionality without unintended side effects.