A friend of mine let me borrow Dune 1-3. I loved them and felt I would definitely re-read Dune. When the deluxe box set of 1-3 came out I bought it but it is just sitting on my shelf. I do plan on rereading them but probably not for awhile. Sometimes I also just like having the books I’ve read on my shelf as “trophies”.
If it’s a book I know I’ll reread, I’ll buy it. I have a kindle, but I much prefer physical books over digital, especially if I happen to find a physical copy for cheaper at a used bookstore. I’m pretty lucky because I have three used bookstores within walking distance from my house and their prices are amazing. I also like buying nice copies of my favorite books from Folio Society or Easton Press. I don’t read those though, they’re more like trophies as you put it.