The adoption and effectiveness of wearable technologies are closely linked to the characteristics and needs of different user groups. Among children, wearables are often employed for safety, activity tracking, and health promotion, while also supporting playful learning and parental monitoring. For adolescents, wearables serve as tools for fitness, social interaction, and self-quantification, reflecting both developmental needs and lifestyle preferences. In adults, applications span a wide range from performance optimization in professional and athletic contexts to stress management, health monitoring, and the integration of wearables into everyday life. Older adults, by contrast, represent a group with specific health-related demands: wearables in this domain are frequently used for fall detection, chronic disease management, rehabilitation, and the support of independent living. Across all age groups, the design of wearable technologies must account for usability, accessibility, and motivational aspects in order to ensure long-term engagement and maximize their impact.