It took me quite a while to learn how to push my limits without hitting my limits. There's definitely an art to this science. And I've hardly perfected it. But, I do like to think of myself as a recovering 'limit hitter.' It's taken a lot to get here. But, it's feeling really comfortable and good now. And I don't want to ever go back to that place I was 2 years ago when work had no boundaries and the 'extraneous' took my life over only to prove, in the end, to be harmful and hurtful.
Here is an example as to how I'm implementing this today. This year we have four wonderful weddings and one social party on the books. These clients all deserve the very best from me. And by accepting any additional business, I would be taking away from what they deserve which is my very best at all times. That's why I have decided to close the books on 2012. I will not take on any additional work this year. By doing so, I would only be taxing myself, my staff, and my family. And this is not something I'm willing to do any more.
Think about your limits. Set them. Then, stick to them. As a recovering 'limit pusher' I can tell you that it feels pretty wonderful to be on the other side!