My PHB is the most worn. The front/back cover no longer stays on the book.
My DMG might be on its way to being in the same state as my PHB. The only thing holding on the front cover is that page with the name of all the authors and stuff.
My Phb is by far the worst off. It's got tonnes of writing in it (plz dont send me virusses or tell me I'm going to hell for that ), and the cover of it is almost falling off b/c I played frisbee with it once.
My other books are fine but that's only because I don't use them as often as the Phb.
PHB is my most worn out book, considering I've only had it 3 years it looks like it's 10 years old at least!!! My old 2e is still in mint condition as are all my 2e books. Seem to be much better quality to me.
My 1st printing PHB is in the worst condition, since I carry it around in my backpack all the time (serves as a spine ofr the backpack) and use it in my games. It is still all in one piece, however, and only has a couple stains on some pages - nothing major. The covers are not going to come off anytime soon either (at least as far as I can tell.) I rarely use the MM, so it is in mint condition, and the DMG sees not much more use either.
Same for me. The cover of my PhB has come unglued completely and the pages have become a bit ragged. The other two have some wear and tear, but nothing too dramatic.