I don't really read books digitally (my poor eyes now I'm in my 30s...) or listen to audio books. However, I do have multiple copies of the same book. I have four editions of The Hobbit, for example.

This is something I find interesting because it brings up the question: are books art in their own right, not simply a format for the story? My answer is YES! I love the look and feel of my Folio society edition, I love the smell and memories of my grandfather's worn copy, I love the annotations in the second hand copy I got from a closing down sale (like the last reader was sharing the experience with me). And I love having a copy I'm willing to give/lend to friends and family that won't break my heart if it's lost.