You don't have a problem until you get the new purchase home, take it to the bookshelf, and find another copy of it already there (did that myself once but not with chess books, it was a history book I had read a couple years earlier and it was republished with a new cover... doh!)
I did it once with the same cover, but I've got a million books, but not about chess. It was a book on astronomy.
I only buy chess books on the topic where I know I'm weak or doesn't have enough knowledge with.