Over the last ten years, the term user-centered design (UCD) has become an essential component of any research proposal that seeks to develop enabling technology for people living with challenging health conditions (assistive technology). While this should be viewed as a very positive development, it is uncertain whether the engineering community fully understands what the term actually means. Is this activity a central component of the work, or just lip service? What do we make of references to participatory design (PD)-is this the same thing? Designability (formerly the Bath Institute of Medical Engineering) has more than 40 years of experience working in this field. In this article, I will review the meanings of these terms, consider some of the challenges of working with people living with disabilities, and detail our experiences of developing successful new designs.