Determining the functional requirements for your solutions is crucial to providing a solution that satisfies your clients' and your needs.

Common client engagements span a range of requirements.
You may have developed the functional requirements or specification for the solution you require.	A Functional Brief for your project (small - large).	A document specifying the functionality required to fulfil your solution's requirements (Small Project).	A document specifying the functionality required to fulfil them your solutions' requirements (Enterprise / Extended Project).

"A fool learns from his own mistakes.
A wise man from those of others"