I've gotten a couple of replies back over a year after I sent in the story. There is just no excuse for a response time longer than a few months, in my opinion. It stands to reason that if a magazine receives an average of, say, ten manuscripts a day, then that editor must reply to an equal number per day, whether it's within a week or a month, or a year of receiving them. I understand that some editors reply faster to Big Name authors, and the longer response time is a tool used to discourage slush. If you're not a Big Name, it can get pretty discouraging.
Writers often complain about the lack of feedback from the editors.
But if an editor holds on to a story for eight months, then it's a bit of an insult to receive just a form rejection. A few neglectful editors never seem to respond to queries. If holding on to a story for a year without explanation isn't abuse enough, when a writer sends a letter asking the status of it, he should expect some kind of an answer. Again, I understand the editor's time constraints, and I'm careful not to bother them with needless correspondence, but when a reply is many months overdue, an editor has a duty to let the writer know what's going on. Another annoying editorial habit is the creeping anthology deadline.