The Importance of Design As managers consider upstream and downstream costs, decision making at the design stage is critical. Although the costs incurred at the design stage could account for only a very small percentage of the total cost over the entire product life cycle, design stage decisions commit a firm to a given production, marketing, and service plan. Therefore, they lock in most of the remaining life-cycle costs As The Critical success factors at the design stage include the following: Reduced time to market.In a competitive environment where the speed of product development and the speed of deliver are critical, efforts to reduce time to market have the first priority. Reduced Expected service costs.By careful, simple design and the use of modular, interchangeable components, the expected service costs can be greatly reduced. Improved case of manufacture.To reduce production costs and speed production, the design must be easy to manufacture. Process planning and design.The plan for the manufacturing process should be flexible, allowing for fast setups and product changeovers, using flexible manufacturing concepts, computer-integrated manufacturing, computer-assisted design, and concurrent engineering. Basic engineeringis the method in which product designers work independently from marketing and manufacturing to develop a design from specific plans and specifications. 4’s common design Prototypingis a method in which functional models of the product are developed and tested by engineers and trial customers. Templatingis a method in which an existing product is scaled up or down to fit the specifications of the desired new product. Concurrent engineering or simultaneous engineering, is an important new method that integrates product design with manufacturing and marketing throughout the product’s life cycle.