In a hyper agile business world the usage of design tools like User Interface Design Style Guides (UIDSG) seems to anachronistic. UIDSG are also biased as being inflexible, hard to manage and rapidly outdated. The opposite is true: UIDSG are still important tools for design management. They unfold their full power if they are based on a straight forward design pattern approach, delivered in ways that keep obstacles of usage for the indented stakeholders as low as possible, and are seen as living documents. In the end UIDSG are most valuable for the development of consistent user interfaces with the return of increased user satisfaction. The authors will present large scale case studies of successfully implemented projects from different domains with insights how to develop, implement and maintain UIDSGs. Finally the presentation will position UIDSGs as communication tool, mediating between stakeholders in a project, speaking different “languages”, like: IT speak, Design speak, UX speak, Domain speak etc.