Transformable products (or transformers), those with two or more functional states, are increasingly utilized by our society. As the mobility and complexity of life increases, so must the adaptability of the products which we use. To develop more adaptable products and systems, we need new design techniques. Transformer design methodology is a discipline with opportunity for expansive development. In particular, the question of deciding when a transformable design is applicable, is as yet unanswered by current research. The purpose of this study is to propose a response to the question “When to implement a transformable design approach?”, by developing and assessing a technical design method. Our novel method identifies, at an early stage in the design process, when developing a transformable product is likely to be advantageous. A brief review of how prior research efforts which categorize transformers has been included. This review helps define what a transformer is, and acts as a segue to understanding when to use transformational designs. Both a deductive and an inductive study are used to identify transformation indicators, primary context properties and usage factors that identify “When to transform?” Our technique seeks to enhance the process of design by simultaneously reducing process complexity and broadening the design scope. The result of this study is a set of basic transformation indicators. Two applications are provided for the use of these indicators: identification of whether transformation is a viable solution branch to a particular design problem statement; and simplified development of new transformers by functionally examining a usage environment or process.