Apart from usage or application scenarios (see tip 10-5) you should consider changes or modifications for quality requirements. This covers arbitrary change requests, like:

• additions or modifications of functional requirements (i.e. modified calculation or validation rules)
• adaption to modified quality requirements (i.e. improved performance or throughput requirements)
• reaction to changes service-level agreements

Such change scenarios cover the important quality goals of maintainability, modifiability, changeability or flexibility.

Some examples:

• Integration of a new (external) payment provider is possible within a maximum of two person-weeks.
• The data format of the yearly booking report can be adapted to the statuory (legal) requirements within 80 person hours.
• The system must be usable with the database systems DB2, Oracle and MySQL without source code modifications.