a cut-and-dried decision is totally hackneyed, and a standard phrase often used in management communities expressing that something is settled and does not need much thought or discussion; altogether something managers like: being (or pretend to be) a man of action, instead of reflecting making boring, standardized decisions and seal the deal with the equally boring phrase. Subjectively to me it feels like a typical term at the hair-dressers’ for the simplest way of treating your hair: wash–cut–blow-dry.

Its origin disputable: most interpretations (deriving from the early 18th c.) refer to timber which is cut to standard sizes and dried before used. There is one other guess: English herbalists cut and dried the herbs before selling them; thus, the herbs had a much longer shelf life contrary to fresh herbs.