I have my favourite books, the bones of my library, that are like "comfort reads", I love snuggling down and re-reading them when the mood hits (Agatha Christie, PG Wodehouse, Dick Francis, Arthur Ransome,...). These are the books I lugged over to Menorca (another island in the Balearics, where I live) when I moved over there for a few years (but I left everything else except my clothes!). Other books I also re-read, but not as often. And some books are good for being read once and never again.