I've also done this frequently. A similar alternative is to decide that I'm going to get out of bed when the time on my digital alarm clock flips to the next minute. That's also turning over the decision to an automated process, but in this case I'm not even in control of the automated process -- I can abort the countdown from 10 if I'm really lazy, but not stop the clock. I think I find this latter method slightly more successful, though I certainly don't have any numbers on it.