Also, monitoring and controlling phase plays a very important phase, since we need to measure the results against baselines during this stage. I think Calculations in any project is a very important part to stay in the range of allowed budget.Its very important to monitor the team performance.So, I think the monitoring and controlling phase is the most important phase in the project life, since we need to monitor schedule, budget, resources, and the team performance.But we need to remember for any project you plan it then you do it.