Dave55, No, I wouldn't try to sell a sub on a 1 circuit job. I rarely do a 1 circuit job but when I do, I sure appreciate it when the original sparky planned for that eventuality. I was talking about new construction in my post. What do you think would prompt a weekend warrior to move breakers around? There would be no reason to move breakers in a 40ct panel as there are no positions available for tandems unless the weekend warrior was going to defeat the tab on the breaker and install a tandem anyway. But then we're back to the fact we all must face: You can make an install idiot resistant but not idiot proof.