Do you really need formal requirements?

Informal methods, such as heuristics to identify users and choose system attributes and functions, can be a highly effective approach for developing requirements. More formal methods may not be necessary. The paper discusses the reasons for spending valuable resources on a requirements effort in the first place: to improve everyone's understanding of the customer's problem; to reduce the risk of uncertainty and ambiguity about that problem; and to provide a foundation for validating your design.