Physics is a degree that supports many career paths, and students often develop preferences for particular methods, such as theoretical, computational or experimental. However, it is not well understood how those preferences develop and affect students' later career decisions. We used Social Cognitive Career Theory (SCCT) as the basis for interpreting students' decision-making processes. SCCT provides a framework for connecting learning experiences, self-efficacy, and outcome expectations with students' interests, goals, and decisions. Semi-structured interviews with 8 physics students were conducted. This analysis focuses primarily on a single student to provide space to explore all three method specializations (theory, computation, and experiment) in more depth. We find that the availability of resources and learning opportunities had a significant impact on students' career choices. Theoretical and computational experiences were readily available through classwork, undergraduate research, and could be worked on at home and in peer study groups. Students lacked the ability to work on experimental physics outside of infrequent classroom opportunities and could not build peer networks that supported their experimental skill growth, which was linked to lower interest and self-efficacy in regards to experimental physics.