Despite an increasing focus on the quality of teaching in postsecondary institutions, little research exists that examines how faculty actually plan their courses in real-world settings. In this study the idea of the "problem space" from cognitive science is used to examine how faculty construct mental representations for the task of planning undergraduate courses. Using data from free lists and retrospective interviews, I report the factors that most shape the planning space and subsequent strategies and curricular artifacts used by a group of 58 faculty. Results indicate the primacy of fixed affordances, such as workload constraints, course content, and class size, and that these constraints contribute to the routine maintenance of preexisting lecture notes and PowerPoint slides. I recommend that educational leaders consider these cultural practices when designing instructional reforms and enact policies that require faculty to engage in brief, postclass reflection that results in minor updates to these artifacts.