Teams must demonstrate knowledge of resource utilization. It is necessary to estimate the types and quantities of resources (people, materials, equipment, tools, facilities, etc.) required to perform each activity. The team should provide a resource requirements plan that illustrates the expected utilization of resources by time period during the time span of the project. Resources can constrain the project schedule. They can also be a constraint to completing the project within budget if it is determined that additional resources are needed to complete the project by its required completion time. It is therefore necessary to take resource constraints into account when developing a network diagram. Leveling the use of resources within the required time frame of the project may be needed.