Why test-driven development?

Each time I enter a discussion with folks not practicing test-driven development, they mostly have one thing in common, which is that it consumes time and resources and it does not really give a return on investment. I usually reply to them by asking which is better, detecting bugs and potential bottlenecks and fixing them while the application is being developed or hotfixing bugs when the application is in production? Test-driven development will save you a lot of problems and ensure you produce robust and issue-free applications.