i don't play WOW or any other MMOG. But I think that old saying that most things in moderation are good for you, seems to apply here as well. I have no concrete evidence to back this and I haven't defined 'most' or 'moderation' but I have noticed that most people understand this intuitively. Are there exceptions, maybe. Particularly, in this community of people, who spend all their time on one idea trying to make it successful. However, I could make the argument that doing it takes a toll on you and your relationships. Anyways, i can't argue it all that well, but it feels like a good rule of thumb.