What are checkpoints?

Question

As I'm making my way through quests in Diablo 3, every so often the message, "Checkpoint Reached" will flash across the top of the screen.

What does it mean to reach a checkpoint? Do you only go back to the last checkpoint when you die?

Answer 1

You'll go back to the last checkpoint when you die, or when the game world has to be regenerated because you exited or got disconnected.