When a Project Manager develops a resource-loaded work-back structure (WBS), the linear distribution of effort between resources is typically acceptable as a starting point to estimate effort and costs. However, there are scenarios where a PM will need to be more granular in the definition of effort within a given time span for each resource (day, week, month) to reflect how the work will be accurately executed. This precision influences two key components of the project planning: Resource Requirements and Financial estimates – which can be achieved with assignments tab.