want to change my apple id email address

When I created my apple account I used an email that I no longer use on a regular basis. I was told by an Apple store employee that in order for me to change that primary address I would have to log out of ALL my apple accounts on EVERY apple device (iphone, ipads, ipods, etc..) first in order to change this. If I don't log out of EVERY SINGLE ONE, it won't work and will end up messing up my account. She was very adamant that I had to do this .

Is this true, and can I change my apple id to a more current email address I use without having to do this?

Thank you,