Throughout the years it has proven difficult to increase independent mobility of individuals with blindness and low vision (BLV) through new mobility aid proposals. A fundamental reason could be that in the common practice of mobility aid design; user needs, established field knowledge, and user-centered design practices are not properly considered. To address this, this chapter presents the generalizable Desire of Use (DoU) model, its application on mobility of BLV individuals (DoU-MoB), and a questionnaire (DoUQ-MoB) derived therefrom. How these can be used for aid design and evaluation is also exemplified through how DoU and DoU-MoB have been utilized in the Audomni electronic travel aid project. This includes specific design choices, design of test methods, creation of evaluation tools, as well as formulation of overarching project aims and long-standing research questions. In addition, DoUQ-MoB is discussed in-depth. It allows to systematically collect self-reported data of a comprehensive set of mobility aid aspects and facilitates the comparison of aids from a user's perspective—avoiding the common issue of assessing proposals isolated from a real-life context. It adheres to best known questionnaire practices and has been validated with orientation & mobility experts, piloted with BLV respondents, and field-tested in a user study.