Concept: Use Case Granularity
Use cases can be written with different levels of detail depending on the needs of the project and stakeholders.
Relationships
Main Description

Use case granularity refers to the way in which information is "chunked" or organized within use case specifications, and to some extent, the level of detail at which they are written. Achieving the right level of use case granularity eases communication between stakeholders and developers and improves project planning. Essential Use Cases are one example of use case granularity. Functional Decomposition is a level of granularity that will hinder a project in both of these areas.

Use cases are often written in specific, granular interaction statements - "The actor does x, the system response is y" - at the level of a function or operation of the system. Such a level of detail has a place in many situations, such as test scripting. It is also beneficial to write use cases at a coarser level of granularity with less detail when it's not required. This can help focus use cases on the goals of the system and reduces unnecessary clutter.