I was rooting around, deleting the backup from my old phone when I noticed my last iCloud backup was a week ago! It says the phone will back up when 1. Plugged in 2. On WiFi 3. Locked Which got me wondering...I use it as a bedside clock every night so it never fulfils all of the above criteria, but my iPhone 4 was used in the same way, running 5.1.1 and it backed up automatically every night Has this process changed since iOS6?