Not all bug out bags are created equal. Given that you may be in a different location, climate, circumstance or other such situation, your needs will differ from that of others who would like you to believe that all bug out bags should contain the same basic elements.
72 hours is not enough! Learn how to maximize what you have and plan for re-purposing the contents of your bug out bag for longer duration if necessary. You need to know what to include in both long and short term scenarios to make it to your destination safely, even if your intended plan changes dramatically.