Do I need to buy currently owned books for my kindle?

Yep, you get no credit for owning the paper version.

One disadvantage of the Kindle is its lack of support for ePub books. And there are millions of public domain ePubs available from Google Books and Project Gutenberg.

Doesn’t help with copyrighted titles, but still, that’s a lot of books.

Only if you want to read them on your Kindle.

Just get again your absolute faves, like those books you have read and find there is something in them that is so meaningful to you that you find yourself going through over and over. It would be great to also have them on your Kindle so that you can check on them wherever you are.
I had my nephew —who is an avid reader— stay with me for a few months before he started college. His suitcase was full of his fave books and I asked him if he hadn’t read all of then already, he said he had but felt better having them with him in case he needed to look for something. On his way back home he couldn’t take them back with him—long story— and those books are now with me. He will eventually get them back, but in the meantime, he has to do without them. It would have been great for him to have a Kindle and his fave books, so he wouldn’t have had to go through the hassel of carrying a load of books back and forth.

For the same reason you have to buy the CDs even though you had the cassettes, and had to buy the cassettes even though you had the LPs, and had to buy the BluRays even though you had the DVDs, and had to buy the DVDs even though you had the VHSs.

You bought a physical book. You did not buy a license to that book’s content on all future mediums.

@jaytkay You can convert those epubs into mobi format with Calibre, and then read them on your Kindle that way.

Yes you would have to pay (assuming your paper books are even available on the kindle at all). The paper book you bought doesn’t grant you the right to get another one in the same or any other format. If your paper book got damaged or lost you can’t go into a bookshop and demand they replace it for free; you purchased one single copy only. Likewise if you decided you wanted it as an audiobook. You bought only one paper version. Any other format is extra.

The good news is that electronic editions are almost always significantly cheaper than paper ones, and anything that’s out of copyright (most literature over 75 years old) is free. If you’re into science fiction and fantasy, it also seems to be a common thing for writers to release the first book of a trilogy as a free e-book, while the remaining volumes are not free. Great marketing strategy.

Legally, you need to buy those books again.

Ethically, the answer might not be so clear-cut.

Some people argue that when you buy a dead-tree book, you are paying for the content, not the medium through which it is conveyed. Continuing along that line of reasoning, since you already paid for the content, you should be able to download an electronic version of the book you purchased.

Note: I’m not condoning piracy, just presenting the other side of the argument.

Sheesh. How did I miss the obvious? Please add to my answer:

”... and had to buy the paperback even though you had the hardcover, and had to buy the audiobook even though you had the paperback”.

@drdoombot That wouldn’t be a sufficient argument for why someone else should provide you with the book in a different format. Purchasing a CD gives me the right to load it onto my computer, but it doesn’t give me the right to demand MP3s from Apple’s iTunes Store.

Thank you for all your expert opinions and advise. It’s been most illuminating. I’ve decided though, to forgo the purchase of a kindle. Books have been around for thousands of years and have not changed. My book library will still be here in fifteen years for me to enjoy. Today’s kindle will probably be in a museum by then, certainly not usable.

Books 1 – Kindle 0

Your books are subject to loss, theft, fire damage, water damage, and child damage. Once so damaged/lost, they are irreplaceable.

Kindle books are subject to none of those. If the Kindle itself is so lost or damaged, and is not covered by warranty or insurrance, a new one can be purchased, and all your books are instantly available again.

Books 1 – Kindle 5

(and there’s absolutely no reason to suspect the Kindle won’t be usable 15 years from now. Quite the opposite, actually.)

@MrItty There’s actually quite a bit of reason to think the Kindles of today won’t be any good 15 years from now. You might be able to charge it and read the books you put on it now, but technology keeps changing, and what Amazon will be selling in 15 years (if Amazon is around) will most likely be a format that isn’t compatible with the Kindles of today. Hell, the Kindle 1 has some issues with compatibility with the Kindle 3, and that’s just right now.

@MyNewtBoobs citation, please, for these compatibility issues. The entire platform of the Kindle is “Buy once, read everywhere”

I think there are two issues getting mixed up.

1) The hardware. Will your current Kindle be used in 15 years? Extremely unlikely.
2) eBooks. Will the ebook you download today be available to you in 15 years? That depends on if you keep a backup copy and will Amazon’s Digital Rights Management (DRM) allow you to read the book on future devices?

@jaytkay Amazon keeps the books on their servers. That’s how you synch between multiple devices. And yes, books you bought last year are available on devices you buy today. Your books are tied to your Amazon.com account, not any particular specific piece of hardware.