I used to back up my kindle then I stopped because I was under the impression that it wasn't really necessary. Man, Amazon just pulled the wool over my eyes.
When I have a lot of CDs and a lot of books, these things have value. They can be passed on to heirs or friends or donated. But in the world of e-mail, we give that up completely. That is significant. Others are earning huge profits by seducing us into the new-fangled things. I've a lover of all things tech, but some things are just better done the old ways. If I cannot pass on my licensed content, is that really a good thing? We have been turned to the dark side and didn't even notice. And, those like Amazon have ensured themselves future profits by re-selling the content to my heirs! It's both brilliant and evil!