On the other hand - and following on what I was saying about taking each book on its merits - I do take some things into consideration. For example, availability. Take Tolkien's 'Old English Exodus'. Many years ago I bought a copy without a dust-wrapper, because I couldn't be sure of when another might come along. This copy has a label - 'Ex libris Peter Clemoes'. Clemoes was an English scholar, with a slight link to Tolkien.

When a jacketed copy came up several years later (again for not a lot of money) I jumped at it. It has a bookplate fromChrist Church, Oxford; with a printed note that this book had been purchased for the personal use of Richard Hamer. I like that; Hamer's edition of Anglo-Saxon poems (with A-S on one page and a modern translation on the other) is a favourite of mine.

And then there's the books with Michael Tolkien's bookplates; but they're not uncommon...