Sufficient funding must be available to fulfill the identified requirement. Cost estimates must consider not only all relevant costs at the preliminary stage, but should also consider possible cost changes over the life of the project. The Develop Preliminary TCO Estimates task of USPS Supplying Practices Process Step 1: Identify Needs will provide the methodology for calculating these estimates. There should also be continuing confirmation from within the organization that funds are available, which is discussed in detail in Section 1-5, Assess Resources.