Then the writing. If double-shipping meant getting two regular issues in a month, I could see the appeal. But more often what happens is that the story starts to feel padded to fill space, and you end up getting the same amount of story content a month, but spread over two issues. Most times, it seems like writers can't write far enough ahead, quickly enough or well enough. Things start to feel rushed and sloppy. It's one thing for a writer to be working on two books. But to write twice as far ahead on one book seems to be more difficult. So, in the desperate rush to stay caught up, they spread small ideas over larger stretches of book, and the stories get a lot less enjoyable.