Academic design research has developed a rich collection of knowledge and tools, but often the results fail to land in design practice. We conducted an interview series with experienced design professionals to study how the knowledge that they derived from research projects was of use to them. They used tools, papers, books, and their own experience in research projects to learn about designing, about the application domain and about project organisation. We found that useful knowledge for design practice can take various formats, including prescribing tools which serve as demonstrator and a reference frame. We discuss how academic researchers can use these insight to make their research more applicable in a way that meets design practice needs.