I discussed non-functional requirements in my previous post “15 Areas to Think About When Writing Non-Functional Requirements.” Non-functional requirements are the requirements that stakeholders and users haven’t thought of, but you have to because without them, the system will fail. If you don’t collect non-functional requirements, then you will not be creating a system that ...
Non-functional requirements should be defined when you are also creating and writing functional requirements. These are requirements that detail the constraints and quality standards that the system you are building should adhere to. You can find out what these non-functional requirements should be by your experience, interviews, and industry standards. Also, you can use functional ...