Greetings! I have three MAC's my latest one is Mavericks 10.9.1. I've never used iCloud before so I thought I'd give it a try since it seems like a good safety feature. Anyway, is iCloud supposed to be left on (don't sign-out?) I purchased 15gb of storage will it back-up all the items I have checked, i.e., Calendar, Contacts, Keychain, Back to my Mac, Find my Mac, etc., or am I just whistling in the dark? Cheers!