My suggestion is to get Calibre, install the DeDRM plugins, and then every ereader works with the Kindle store. You would lose the wireless integrations with Am

My suggestion is to get Calibre, install the DeDRM plugins, and then every ereader works with the Kindle store. You would lose the wireless integrations with Amazon on some non-Amazon devices. If that's important to you, then this might not be a great solution. But otherwise, it's the best way to go. Not only could you then use any device on the market, but your books are truly yours. Immune to Amazon revising them in the future, and immune to having your books revoked. They'll last as long as your preferred backup methods last. And that's a good reason to do this even if you keep using Kindles.