I'm a jacket on kind of girl. I'm all for keeping books, especially rare ones, in nice condition. There is a flip side to this though. I think that there is someting rather charming about a battered volume, regardless of age, whose continued existence is thanks only to the adhesive power of sticky tape. Someone thought highly enough of the book to want to preserve it in their own way. Page corners may bear the scars of have been folded over in various places, perhaps to mark a favourite passage or a place that a previous owner did not venture beyond.
I have lots of crisp, clean books with dust jackets present and intact. But then again, I also find something comforting and heartwarming about a much read and repaired edition that has passed through many hands before reaching mine. There are many of these on my bookshelves, and I find that they are the ones I return to the most.
Grace.