Design consideration for tailoring users’ decision-making experiences is viewed as an important factor towards more highly user-centred and personalized human-product interactions (HPIs). In this paper, we aim to establish a foundation for a new design approach by presenting the set-up of the development and validation of a new measurement scale on users’ decision-making tendency, maximizing and satisfying. From behavioural science, we extend the recent discussion on these individual differences between maximizers who tend to expect the greatest amount of benefit from every daily opportunity and satisfiers who tend to feel happy with their choices as long as they think they are good enough. We developed an initial pool of the decision-making tendency measurements based on previous literature and a focus group interview. To modify the initial pool of measurements, we conducted (1) random probes with three researchers and (2) standard scaling procedures with eight external judges. Furthermore, we tested the reliability of the scale by calculating Cronbach alpha and test-retest reliability. We expect that these findings provide a grounding for future design research and practices in terms of implementing users’ decision-making tendency for personalized HPIs.