Maintaining mental models: a study of developer work habits

To understand developers' typical tools, activities, and practices and their satisfaction with each, we conducted two surveys and eleven interviews. We found that many problems arose because developers were forced to invest great effort recovering implicit knowledge by exploring code and interrupting teammates and this knowledge was only saved in their memory. Contrary to expectations that email and IM prevent expensive task switches caused by face-to-face interruptions, we found that face-to-face communication enjoys many advantages. Contrary to expectations that documentation makes understanding design rationale easy, we found that current design documents are inadequate. Contrary to expectations that code duplication involves the copy and paste of code snippets, developers reported several types of duplication. We use data to characterize these and other problems and draw implications for the design of tools for their solution.