The rise in the open-source hardware practices, and Do-It-Yourself and Maker movements through newly-developing internet technologies (e.g. Wikis and user-generated content), and the dissemination of end-user focused digital production technologies (e.g. 3D printers, laser cutters, etc.) helped design practice evolve towards a more inclusive process. Open Design approach presents a continuous process of co-designing that is open to everyone, with no limitations on time, space and kind of contribution. In literature, this approach is mentioned to reveal opportunities for sustainability concerns such as repair, reuse and upgrading of parts and products, due to its transparent process of sharing design data. However, as a newly-developing approach, the practical opportunities and the implications of it for sustainability have not been questioned beyond its observable possibilities. The purpose of this PhD study is to shed light on the question of adopting open design approach for sustainability concerns of product/part longevity, personalization and part reuse, and to explore the implications of open design for these concerns to transform already established product types (i.e. small kitchen appliances). For this purpose, research through co-designing methodology was developed and applied through the utilization of two different design workshops on practices shaped around small kitchen appliances. The study revealed sustainable design considerations for idea-generation, open part properties that respond to these considerations, strategies of adopting and iterating open design solutions and their implications for product/part longevity, personalization and reuse.