You Can Get AppleCare Anytime Within the First Year — and Here’s a Deal
AppleCare extends the warranty on a Mac to 3 years (and includes the display if purchased with the Mac). It also includes enhanced support and service, and in general, makes the warranty worldwide.
With a new Mac, you don’t need to buy AppleCare right away, you have up to the end of the first year to buy it. But since Apple charges full fare, looking around is a good idea.