Franke & Piller (2003) stress the success of mass customization (MC) depends upon optimal toolkit design and underscore the importance of the MC co-design experience. However, what do we know about the value of this experience? How do we increase its value? How do we optimize toolkit design? Based upon the academic literature, this paper aims to answer these questions. First, we discuss results of previous studies on the four key variables used to assess how the consumer values self-design: enjoyment, control, pride of authorship and complexity. Second, we analyze the best solutions to increase the value of the co-design experience on these key variables: we explore toolkit functionality and how it can be endowed with features that enhance the MC user's perception of the process. This paper contributes to the body of mass customization theory regarding the value of the co-design experience and emphasizes how to design efficient toolkits.