I may be in the minority here, but sometimes I buy the same book twice. Or maybe three times. We have books and bookshelves all over the house, and it's hard to keep up with what I already have, especially children's books. (I'm not generally a hoarder of things, but I do sort of hoard books...)
I've found a neat iPhone app that's helping me get organized, and thought I'd share it with you, as most of us are looking for a little organizational help this time of year. It's called Book Crawler, and it sells for a whopping $1.99. (I should mention that I'm pretty cheap, and rarely pay for apps. This one is really worth it.)
There are several ways to import your book collection, but the quickest way is by scanning the ISBN number. (Even then, it's taking me a while to scan hundreds of books, but it will get done eventually.) After importing your books, you can categorize them several different ways, by topic, author, etc. When the kiddos and I are looking for books about a given topic, like space, I can easily look and see what we have.
When I'm making my weekly book buying Goodwill trip, I can scan the books' barcodes to see if I already own them, which is pretty awesome.
What apps are making your life easier?
(I have no affiliation with the makers of this app, I just wanted to share something that's working for me.)