In this article, the research group Performance without Barriers reflect on the process of collaboratively designing a custom guitar-inspired instrument with Eoin Fitzpatrick, a physically disabled musician from the Drake Music Project, Northern Ireland. As part of a longitudinal ethnographic case study designed to uncover factors that contribute to the longevity of custom assistive music technology, the authors monitored Fitzpatrick using this instrument over two months. The findings of this study inform a reflection on the social, technical, and environmental factors that the provision of such technology a reality. The authors make suggestions for ways to achieve long-term, sustained use. Custom technologies, seemingly unique on the surface, may well utilize similar underlying hardware and software components. Those involved in its design, fabrication, facilitation, and use could benefit from a concerted effort to share resources, knowledge, and skill as a mobilized community of practitioners. In such a pursuit, the authors recommend that practitioners consider strategies for managing the inherent complexity of digital technology. Fostering shared mental models within open-source communities can result in improved efficiency in the development of accessible music technology.