I have owned oak veneered Billy bookcases for almost 18 years. They have never warped, drooped or collapsed, despite being heavily laden with my weighty tomes in the spare bedroom. The micro-thin veneer has never lifted, and has, in fact, mellowed nicely in colour over the years. They do an effective job. I use small tacks to ensure the thin back panel is closely attached to the shelves, and does not gape.