Self-tracking technologies (STTs) in the form of smart devices and mobile applications enable consumers to monitor, analyze, and interpret personal performance data on health and physical or financial well-being. As a result of self-tracking, consumers are not only expected to check their personal performance more actively but also to implement service professionals’ advice to improve their well-being more accurately. Despite the growing popularity of STTs, empirical evidence on the extent to which STT use enhances advice compliance remains scant. A field experiment with 538 participants in a health-care setting suggests that STT use does not increase advice compliance per se. Rather, the effectiveness of STTs depends on consumers’ self-efficacy. For consumers low in self-efficacy, STT use can even undermine advice compliance. A lab experiment with 831 participants replicates and generalizes the findings to a nonmedical professional service (i.e., fitness training). As assessments of self-efficacy might be difficult in practice, service providers in health care can use consumers’ body mass index as an easy-to-measure proxy to predict STT effectiveness. Finally, the lab experiment also identifies perceived empowerment and personalization as psychological mechanisms mediating the influence of STT use on advice compliance.