Summative assessment is often considered a motivator that drives students' learning. Higher education has a responsibility in promoting lifelong learning and assessment plays an important role in supporting students' capability to make evaluative judgements about their work and that of others. However, as research often focuses on formal pedagogical design, it is unclear what behaviours summative assessment prompts, thus the relationship between summative assessment, learning and evaluative judgement requires further investigation. Drawing on a small-scale ethnography-informed study, this paper adopts a practice theory approach to explore how undergraduate physics students from three year levels make evaluative judgements in the context of summative assessment tasks. The contexts explored through observations and interviews include a graded in-class tutorial, an out-of-class study group for an in-semester assignment, and individual preparation for examinations. The findings suggest that while summative assessment is a crucial aspect of students' learning context, it does not fully shape students' practices. Instead, students engage in incidental conversations about the quality of their work and how to do things in their studies. By focusing on what students "actually do," this study integrates formal and informal aspects of students' learning, highlighting the tensions between undergraduate practices and intended learning outcomes.