Well, it only took me 30 years and we won't mention how many dollars, but I've done it. As of today, I'm the proud owner of an American 1st edition of every Agatha Christie published. What started out as a nice way to read books, back in the 70s when hardcovers were only a few bucks, grew into a collection. I was probably 5 years and 25 books into the project before I even thought of it as one.
Many of my collections got my start back then. Craig Rice, Ellery Queen, my Van Dines, and more. A few kind collectors (like Bill Dunn!) helped me find editions and books that I might not have found otherwise. I had to shop then by mail or phone, rushing to call and buy a book before someone else found what I was looking for.
Now I can just sit at home, go to one of many bookselling sites (including good old eBay, which I adore) and get the book I want. Some of the challenge is gone, being replacd only by finding a way to fuel my addiction. And in a family that has too many deadly addictions, I have to say that I'm glad to have only inherited the collecting gene.
So the last of the books (which was The Murder of Roger Ackroyd for those who might want to know) is winging its way to me as you read. Who knows what I'll collect next, but I'm sure it will be something.