Traditional product development methods take more time than is generally acceptable today. They also treat time as an important but secondary consideration, beginning the planning process with a set of assumptions about the steps involved and only then asking, "How long will it take?" We have developed an approach that we call timescale–driven development, which sets traditional methods on their heads. Time–scale–driven development allows new products to be developed much faster – even when they involve high technical risks or regulatory requirements. With timescale–driven development, we know how long we have – the question is what must we do and how must we do it before the deadline. Having a defined end date shapes the planning process, dictating how much time can be apportioned to certain fundamental activities, such as soak tests and tooling manufacture. The process even determines to some degree the specification – the number of prototypes that will be necessary, the resources that will be required, and whether resources must be found externally.