Once upon a time, my books were my books. Even ones I wasn't particularly fond of were still mine - that meant I would never lend them to anyone. Ever. Why not? I think I just had a thing about owning books (no, I didn't have lots of my own books as a child). Perhaps because I'd been a librarian, lending out thousands of books every week to everyone, and seeing the state they came back in - if they came back at all - maybe that made me paranoid!
But gradually I met up with lots of writers who felt the same as me, and cautiously I entered into an agreement whereby we would very occasionally lend to each other and return the books as soon as we could. Anal, I know. But not unusual, from what I've heard. When I started buying writing how-to books, which were often very expensive, I "teamed up" with my friend T, a writer and teacher like me, and we decided we'd try not to duplicate books and build a joint library, and lend to each other. This has worked really well, and if we borrow one that we end up loving, we can then buy our own copy.
But I was still loathe to lend my other books, the ones I'd enjoyed and planned to read again one day. Because lots of people forget to return books, and unless you keep a list (anal again) how can you remember who has what? Then the prices of books starting rising, and rising, and rising. Currently, a new trade paperback is around $36 (yes, if you live in the USA you can start hyperventilating now). A mass market paperback is around $22-25. Don't even ask what a hardback sells for - all right, it's between $45-50.
I have cut down the number of books I buy simply because of cost. I am going to the library a lot more. But at the end of the tax year this year, when I added up my receipts, I had spent around the same amount as in previous years - but I knew I'd bought fewer books. One of the results of all of this, strangely enough, is that I've started lending! Somehow, I've come to the conclusion that if a book is going to cost me that amount of money, I want to make better use of it. So rather than stick it on my shelf and let it collect dust, I'm lending.
When it comes to ebooks, I think this might be the crucial make-or-break factor - whether you can lend your ebooks to friends. I see that Amazon are already looking at a scheme where you can lend your Kindle book to a friend for two weeks (and then I think they rip it back off you - which I think is a very weird strategy and will backfire on them).
So what about you? Do you lend? Who to? Do you keep lists? Do you borrow? Are you a chronic non-returner?! Or are you a hoarder/non-lender?