Used like maps, documents can help to keep you and your organisation on course. Used as records, they can help to show where you have been and how you got where you are (see section 8.3, Records management). The danger in documentation is that it can be misused as wallpaper, used to paper over the cracks in the management system.
Documentation should be kept at an efficient minimum. The litmus test for seeing if a document is a bureaucratic nicety or a necessity is if you know why you need it. Keeping documentation at an efficient minimum is easier said than done, because when you begin to think, you will discover you may need a lot of documents.
With all the emphasis on law in environmental protection, documents can be a valuable protection against lawsuits, records showing that your organisation was working in conformity with regulations.
And documentation can be a way for new employees to find their way quickly and easily around should they need to, and for old employees to find out what they need to when working outside their normal area of operations.