Wearable computing has gained significant traction with the advancement of computing technology and the resulting increase in efficiency and power within smaller form factors. The interfaces and applications of these devices have evolved over centuries from very primitive implementations to those which adapt to and anticipate user needs. However, the principles of human-centric design have only recently been defined and understood in the context of wearable computers. These devices introduce an additional set of requirements to the traditional concepts of human-centric computers which have yet to be defined in an adaptable framework. The failures of many recently launched wearable devices highlight the importance of these considerations throughout the design and development process. Human-centricity currently serves as one of the major challenges to the ubiquity and future success of wearable devices.