As part of my clean up of my digital life, I decided to retire an email address, and my Apple ID was on that address so I needed to change it.
There's no doubt that changing the email address associated with things like your Apple ID can be scary. What if it goes wrong? Most folks have a lot of $$ / ££ / €€ invested in the iOS ecosystem.
BTW this doesn't solve the multiple Apple account problem. One day maybe Apple will solve this.
Here's the process (information gathered from Apple's help system, and personal experience).
- sign out of your iOS devices:
settings > store
- sign out of itunes
itunes > store > sign out
- goto appleid.apple.com and follow instructions from support.apple.com/kb/HE40
- login by selecting 'manage your account'. Use using existing (old) email address / password
- in the section for "Primary Email Address", click edit
put in new email address, click save, and it'll generate a verification email
- If you try to run the verification too soon, you'll get an error saying something scary like the address is already in use.
so, give it a few minutes, and re-login to iOS and iTunes, the try the verification again