From the official Stephen King Facebook page:
I used to tell interviewers that I wrote every day except for Christmas, the Fourth of July, and my birthday. That was a lie. I told them that because if you agree to an interview you have to say something, and it plays better if it’s something at least half-clever. Also, I didn’t want to sound like a workaholic dweeb (just a workaholic, I guess). The truth is that when I’m writing, I write every day, workaholic dweeb or not. That includes Christmas, the Fourth, and my birthday (at my age you try to ignore your goddam birthday anyway). And when I’m not working, I’m not working at all, although during those periods of full stop I usually feel at loose ends with myself and have trouble sleeping. For me, not working is the real work.