5 Situations for Writing Use Cases

What are five common project situations for writing use cases?  In Writing Effective Use Cases (Agile Software Development Series), Alistair Cockburn identifies five different situations for writing use cases to help you better understand variances between the purposes and approaches.

Five Project Types
Cockburn identifies the following five particular situations:

1. Eliciting requirements, even if use cases will not be used at all in the final requirements document.
2. Modeling the business process.
3. Drafting or sizing system requirements.
4. Writing functional requirements on a short, high-pressure project.
5. Writing detailed functional requirements at the start of an increment, on a longer or larger project.

I think a helpful question to keep any tool or template for use cases on track is to ask, who needs to know what, and what’s the simplest way to share, in a way that’s easy to update or change.  Built to change over built to last.  I think the worst mistake is capturing a lot of information that gets in the way of what people really need to know, or that makes it difficult to easily respond to evolving information needs.