I had to rebuy JW's Greatest Hits 1969-1999, because my girlfriend's father, to whom I lent it, lost it. But, luckily enough, that was the only case. Otherwise, I bought several CDs twice simply because they're so great, several examples are Miles Davis's Kind of Blue, Dream Theater's Metropolis Pt. 2: Scenes From a Memory and JW's Star Wars - A New Hope.