Prior self-service technology (SST) studies focus primarily on the initial adoption and its drivers. However, the long-term viability and success of an SST depend on regular and frequent usage. Therefore, this study draws on social psychology and information system/information technology literature to investigate the habit of SST usage and its driving forces. Using panel data pertaining to 626 Australian customers who used a supermarket self-checkout machine over 12 weeks, the results reveal a strong carryover effect of habit. Satisfaction and self-efficacy positively contribute to habit development. Past behavior exerts an impact through frequency and recency effects. Moreover, the driving forces of habit are more complicated for men than for women. The findings provide important implications for service providers planning technology upgrades. The results suggest that to prevent habit disruption, gradual improvements are a better and safer strategy than introducing a new, disruptive technology.