I have been arguying with a developer who insists that 1 functional request (FR) == 1 use case (UC). I think that is nonsense as there are requirements often describing situations arising from the same point - for this the use cases have alternate flows.
FR01 - User can log in FR02 - User's account will be locked after 3 incorrect passwords. FR03 - Logged user can log out
I believe all these can be nicely captured within a single use case, describing the interaction between the user and the system.
But maybe I am missing something?
EDIT: According to the book "Use Case Modeling" from Bittner, Spence:
a use case contains a set of description of requirements, the requirements are presented in the form of narrative rather than an itemized list...
So I would say definitely more requirements can be captured within a single use case.