Quantified-self technologies (QSTs) provide functions for users to collect, track, and monitor personal data for self-reflection and acquisition of self-knowledge. Although QSTs require prolonged use to reap the attendant benefits, many users stop using their devices or tracking within weeks or months. To address this issue, this study seeks to determine ways to sustain the use of QSTs. Combining motivational affordance theory with technology continuance theory, this study develops a theoretical model that accounts for an individual's continued intention to use a QST. Within the proposed model, unique QST affordances were identified as antecedents of individual motivation in relation to technology continuance, and their different roles in stimulating hedonic, utilitarian, and eudaimonic motivations were examined. The model was tested using data collected from 180 QST users. Results demonstrate that although utilitarian and eudaimonic motivations are complementary forces in determining continuance intention, hedonic motivation loses its predictive power in favor of eudaimonic motivation. Tracking, visualizing, and sharing affordances play different roles in elevating user motivations. The sharing affordance does not influence utilitarian and eudaimonic motivations, but it positively influences hedonic motivation. This research contributes to the literature on technology continuance by shifting scholarly attention from hedonic-utilitarian duality to eudaimonic motivation, characterized by meaning, self-growth, and pursuit of excellence.