The expectation gap
Between user's expectation and what the developers try to deliver exists a gap, and it grows over time. Only frequent user engagement (by arranging frequent contact point) can minimize the gap. And, this gap has to be managed (Beatty & Wiegers, p.168).
Product requirements vs. project requirements
The development of product requirements, housed in the SRS, focuses on what is intended to build (Beatty & Wiegers, p.122), whereas requirements for the development activities, such as bug fixes, tests, and deployments etc., belong to project requirements. Separating these two types enables the team to stay focused.
Requirements development vs. requirements management
Requirement engineering consists of requirements development and requirements management (Beatty & Wiegers, pp.128-138). Requirements development refers to the elicitation, analysis, specification, and validation; while requirements management refers to setting baselines, handling changes, and tracing etc.
