Self-service technologies (SSTs) increasingly permeate retail spaces. To make their SST investments worthwhile, retailers need to turn enough customers into SST users. Previous research has uncovered the significance of habitual behaviour stemming from prior experience and situational factors from the environment on SST use. However, consumers are likely to vary regarding the extent they are driven by either habit or situational factors, suggesting that different types of consumers might exist in this regard. In this paper, we probe these consumer types in a real-life choice situation by studying the choice of selecting a checkout option (either staffed or self-checkout). We conduct a field study employing mixed qualitative methods by observing and interviewing customers checking out from retail stores. We discover four distinct customer types regarding the extent of reflexive (automatic) and reflective (deliberate) processing they use in their checkout selection: habitual traditional checkout users, habitual SCO users, situational users, and drifting users. We discuss the implications of our findings by linking the cognitive processing styles to the different stages of technology acceptance. Our main contribution lies in the development of a typology of consumers based on their selection between SST and human-delivered service.