The requirements for any product you build are never completely unique. We suggest that before starting on any new requirements project, you go through the specifications written for previous projects and look for potentially reusable material. Sometimes you may find dozens of requirements that you can reuse without alteration. More often you will find requirements that, although they are not exactly what you want, are suitable as the basis for some of the requirements you will write in the new project.
Link · 2. The Requirements Process