Traditionally, users have not been involved in certain usability engineering methods, although they arguably are the most important stakeholders. This paper explores the possibility of involving users in developing a set of usability heuristics for a specific type of application, an activity they are not usually involved in. Using a qualitative approach based on interviews, a focus group, and an online survey, usability experts and software users evaluated existing sets of heuristics in terms of their applicability to a specific type of application and developed new heuristics to supplement them. The results indicate that the users provide a valuable contribution to the adaptation of existing heuristics to a specific type of application. Users add a new perspective and can address problem areas that usability experts, especially those with little or no experience with the specific application area, would not have identified.