So here's another question. Is there a way to also use last years magic band? Now I'm all excited about decorating them and matching them to what I'm wearing!
Think of Magic Bands as keys - ALL they do is provide access to your
MDE account. Nothing is "on" them, nothing is "linked" to them and they are all interchangeable.
Each band contains 2 RFID chips in them that provide the computer systems with the access keys to your MDE account.
One of them has a short range transceiver that is used for some ride photos and videos and the occasional special effect such as your name displaying at the end of It's a Small World. This chip has a battery that should last 2-3 years. It's not replaceable. So once the battery on that chip dies, those functions stop working for that band.
Everything else uses the second chip. This chip does not have a battery; it is powered by the touch point at the moment the two come into contact with each other. So all park entry, FP entry, purchases, room access, etc. use that chip, and should work just fine up until Disney changes the underlying systems' technology. Or the zombie apocalypse - whichever comes first.
The result is that EVERY active magic band associated with an individual can be used interchangeably to access any and all of these function. All of you bands are active unless you specifically go into your account and deactivate them. Go ahead and feel free to decorate and accessorize to your heart's content.
There is one area where you may experience some difficulty using multiple bands. Different resorts seem to react to multiple bands being used for one person differently. I have a couple of theories as to why (neither speak highly of Disney's internal systems design, nor of CM training). But you may find that trying to use a band other than the one specifically associated with that resort stay will result in not being able to open your room's door. Everything else will be fine, but you'll have to go to the desk where they will "fix" it. Usually dispensing a ton of misinformation at the same time.
Sorry for the long winded answer to your question. It's the teacher in me - going for understanding.
Steve