Do requirements developed for a project have any residual value, and if so what should I do with them?
Squiggles on cocktail napkins are a great way to make a point, or even talk through a solution. But they're hardly reusable, and they aren't a respected communications medium. If you want to avoid reinventing the wheel every time a project threatens to impact a system or business area, there's no substitute for clear, thorough, reusable requirements documentation. And the requirements documents are reusable when the organization takes on similar projects. In fact, that's a good argument for making the requirements documents as clean, organized, and easily retrievable as possible.