This study presents a quantitative account of who uses or stops using digital self-tracking (ST). A representative sample of German adults aged 20–50 years ( N = 1022) completed an online survey on their ST practices, personality traits and attitudes toward numbers, on sociodemographic characteristics, mental disorders (particularly bulimia, burnout syndrome, and depression) and somatic disorders. A descriptive statistical analysis was performed on differences between self-trackers and non-trackers. Among others, they differ regarding age, civil status, social class, presence of mental and/or somatic diagnoses, performance-pressure, and strive for competition. A consequent binary logistic regression analysis suggests perfectionism, a somatic diagnosis within the last 5 years, a diagnosis of bulimia in the past, as well as a present mental diagnosis to be significant predictors for ST, though the predictive value of the factors was relatively low.