Let’s break down the Rule of Threes, one by one. Want to learn more? Here is everything you need to know about the Rule of Threes in survival. These rules are to act as a guide and are a great quick reference that can help individuals understand their priorities when in an emergency situation, focus on what needs to be done and fall back to that to fight off confusion or fear. However, if you end up on dry land with nice weather, chances are you may live for over three hours. If you fall into a large body of cold water and get stuck, it is highly unlikely you will last three hours. The Rule of Threes states humans can survive: If you are new to the exciting world of prepping or survival, you may not be familiar with the lingo yet -and that’s perfectly fine because that’s why you’re here! One of the rules we have amongst preppers and survivalists is called the Rule of Threes.