What drives undergraduate students to persist in or drop a physics major? To answer this question, staff members at the Statistical Research Center (SRC) at the American Institute of Physics (AIP) conducted a 5-year longitudinal study between 2018 and 2023. We surveyed 3,917 students in the first week of their introductory college physics course and asked whether they wanted to major in physics. The 768 students who were considering a physics major were surveyed annually for 5 years. We compared the experiences of students who graduated with a physics degree and students who lost interest in a physics major. Among the students who left physics, most dropped physics during their first two years due to other interests or issues within physics courses, and they were more likely to report lower self-efficacy and less positive department climates. Underrepresented students who left physics reported less supportive relationships with physics professors and peers.