[taming]

No, I have never lost a book by backing it up, and you can back-up as many times, to as many places, as you wish. Now, if you have what is called a two-way sync, where the actions in one folder are mirrored in the other, then deleting a book in one place will, upon sync, delete it in the other. That is why for my Allway sync set-up, I have it configured as a one way sync--books go into the synced folder, but they never come out--regardless of whether or not they are removed from the folder of origin.

Try them both. I have allway sync set-up so it automatically backs up to another folder n my hard drive without my having to do anything. It just happens in the background whenever a change is made to the original folder. I use Sync-Toys for syncing to my portable drive which is not always plugged in.

You can also store/backup your pictures using a photo site like Flickr or Picasa.