We all have one. The number of hours per week we can work before something slips -- our happiness, health or productivity. Knowing it is Step 1 in achieving balance and creating boundaries.
Mine is 45. Once I work past that, I can't be creative or form the deep connections necessary for my success (Let alone what it does to my health and family life).
I know that sounds low, but most people are lying to others (and themselves) about how much they work. On average people who believe they work 75-hour weeks are off by 25 hours. We remember the bad weeks more than the good ones.
Do you know yours?