I keep all my books on all my devices. On what page, that depends... Sometimes I go back to the first page, sometimes I'll stay in the last one, sometimes I'll go back to a part I want to check again and leave it there.
Originally Posted by QuantumIguana
I used to keep all my books on my Kindle, I really didn't like deleting them. But then I had to reset my Kindle to factory settings, and I didn't feel like putting everything back on the device, so I've gotten more comfortable deleting books when I've finished reading them. I do think that the longer people have e-books, the greater will be the need to have better ways of organizing cloud storage.
I have all my books on external storage and those won't be reset. On my tablet I use the Calibre Companion so that'll be kept updated at all times (at least, as soon as I turn on Calibre and make the connection).