Small projects (like $50,000 or less) may not require your resources put into delivering the work (labor, materials, travel and other costs) to be broken down into more detail; however larger projects typically include a project or work-breakdown structure (WBS) to segregate costs based on work-packages. The WBS is like a series of sub-projects within the main project, with each WBS being a group of tasks, assets, costs, work, resources and timeline to deliver a specific portion of the main project.

WBS elements represent the company's internal view of how to deliver the work whereas the assets or priced/contract line items represent the external customer's view of what is to be delivered.

A WBS is typically used when the project is big, based on a complex  plan, or involves multiple resources to complete. WBS hierarchies or "work breakdown structures" are either entered manually or copied in from a template.