People come back for the characters. You could ask your average Supernatural fan to explain the mythology of a season and they're gonna explain it in terms of the characters they respond to. Sam, Dean, Cas, Crowley, whoever they're into in whatever combination. I think that's the important thing. So as long as we can keep these characters vibrant and developing, and move toward more serialized storytelling that TV in general has done and that we have done, allows that. I think we can keep going for a while. I think what's going to stop us ultimately is at what point do Jared and Jensen decide they've played the roles for too long, or at what point do we get to a point where we feel like we're repeating ourselves, or we feel like we can't take some of the bigger swings - whether they work or not - that we've taken in the past. So for me to give an end date, I couldn't do it. I think we're all really hopeful of getting to Episode 300. We think that would be a really awesome milestone. Could it go beyond that? Creatively, yes, I think it could. But just because something could doesn't mean it should.