I know that once you purchase a book, you won't lose them, even if you switch your country of residence. Once you've purchased it, it's yours, and it will always be in your Amazon Kindle archives on the Manage your Kindle page of your account.
Um, not necessarily. DRM for ebooks usually includes a limited number of downloads, say 5. If you have it on your Kindle that's 1, your smart phone is 2, then you're reading it on your desktop at work when no one is looking and that's 3. You finish the book so you delete it from your devices but then you want to look up your favourite quote so you put it back on your kindle and that's 4, and you remove it again. Now there's a sequel coming out and you want to reread it first so you put it on your Kindle, 5, and try to load it on your iphone but you can't. You used your 5 downloads. It won't disappear from your Kindle, but if you want to download it again, either onto your phone or down the line when another sequel comes out, you have to buy it again.
Same with device limits - if your book has a device limit of 2 and you have it on your phone and your Kindle and you want it on your computer, you'll have to delete it off the one before you can. Some books have lower numbers or higher, and some are unlimited, but the information is rarely listed unless it is unlimited.
A few years ago
1984[/1] and Animal Farm were removed from the Kindle store, I believe because there was a problem with the copyright and they didn't actually have permission to sell them, and they "recalled" them out of people's libraries, and off of Kindles that were connected to the internet automatically. Needless to say this went over badly, but it was perfectly legal.
You do not own digital media the way you own physical media.
