Originally Posted by FizzyWater
If the reader is one that can be used with DRM ADE, then yes, you can authorize the new device. I believe there's a limit to the number of device you can authorize (counting your computer, too). But I've read that if you have an issue with that (for example, if you get a new computer and device, and you've run out of authorizations) you can contact Adobe on their forums to have the number extended.
I just bought a new pc, and I had no trouble authorizing my new pc for use with ADE. I also discovered that I can deauthorize my old pc if I choose.
So I don't think you should ever run into a problem with running out of authorizations utilizing this option.
All I had to do was re-upload all of my books to my ADE library from my ebooks file.