Watch a live coding demonstration that shows how to apply Test-Driven Development (TDD) from the beginning of a project to naturally introduce Domain-Driven Design (DDD) patterns when needed. Start with the simplest implementation of a CRUD system for university enrollment management and gradually add complex requirements like preventing course over-enrollment. Learn to develop DDD tactical patterns including repositories, aggregates, and domain services through incremental refactoring. Experience a dramatic model change mid-demonstration where the enrollment system shifts from preventing enrollments to allowing all enrollments and allocating resources to popular courses, showcasing how TDD tests and well-structured domain models make such significant changes more manageable and demonstrate the maintainability benefits of a DDD codebase.