Let’s first look at an analogy. Think about an HVAC system. What if the condenser went out? What if the controls cabling is cut? What if you open all the doors and let all the outside air in all at once? What if the thermostat breaks? What happens to the system if these things happen? It goes down completely or at least operates sub-optimally. A construction project is the same way! All components must work well, or the project will fail, or at least work sub-optimally.