I usually only buy books that I have read until their spines fell off at the local library so that I may cheerfully do the same thing to my own copy.
Otherwise, I buy books by authors I particularly like, or that a friend lent to me and then inconveniently moved away.
I do not buy books based on their cover art.
Recently it seems that fantasy books have gotten a cover art overhaul, but the old covers of the genre are sometimes outright appalling.
Fish: They’re like romance covers without the beefcake and cheesecake.
Mom: Dragoncake!
Fish: You misunderstand, there is no pinup value.
Mom: I had a Tolkien calendar when I was your age, I pinned that up.
Fish: I think that you should tell Dad about your odd-
Mom: Castlecake!
Truly, cover art is no reflection of the quality of a book, and it happens to the best authors. There are some books I walked around with unblushingly in my relatively innocent youth and yet now dread to leave my house with. At times I am relieved when I have read the covers off, so that I can take them out of my house without cringing. Does anyone else out there have terrible covers to decent books?