AppleCare is insurance against failure, not against loss/damage/theft. Personally I buy one for every Mac I have owned. I buy my computers to use, not to pamper. If anything breaks let Apple fix the problem. I've owned Macs since the last millenium before they were popular

Having said that though, never ever buy AppleCare until the last week of your original warranty (check online to be sure). AppleCare is not insurance. If you buy it the first day, then someone swipes your rMBP on the second day, you're also out of RM799-1199 on top of the cost of your rMBP.