That's the entrepreneur's dilemma. How do you posses enough passion and confidence to make it through the tough times but known when to call it quits.<p>It's the single most difficult part of entrepreneurship. It actually gets harder the further you are along the path.<p>If you give up too early on all your ideas the decision has marginal difficulty. The more you're invested the more difficult it is to decide to throw in the towel.<p>So the more you progress as an entrepreneur the more difficult it becomes.