<p>The Quantified Self (QS) movement promises to enhance personal freedom by using technology to track and optimize human physiology and activity. QS technologies like fitness trackers, smartwatches, and mood-tracking apps have been growing in popularity and are widely credited for improving mental, physical, and emotional health. This article examines how we might best understand and respond to the challenges posed by QS technologies. Adopting an ethnographic approach and employing Charles Taylor’s framework of self-interpretive freedom, it analyzes publicly available primary evidence. Critics question the benefits of QS technologies and highlight the potential harms associated with technological self-surveillance. Proponents encourage an expansion of QS technologies as a means of transcending the limits of unaugmented life. QS practitioners need neither blindly surrender to self-tracking technology nor lose their humanity when deploying it. Rather, their technologically enabled activities can enrich self-interpretive freedom. As digital human twins and AI-driven self-tracking tools evolve, their development and use are best guided by this principle: that technology should serve, rather than supplant, the temporal, dialogical, and embodied dimensions of human agency.</p>