Concerns regarding smartphones’ and social media’s impact on youth remain high amidst a growing realization that current research is not designed to confirm (or refute) such concerns. This study aims to answer fundamental questions regarding youths’ use of smartphones, by implementing a novel user-centric research method. The smartphone use of 114 emerging adults was recorded, followed by in-depth interviews that incorporated the recording and in-app information to help participants recall their behaviours, motivations, and feelings. Results indicate that smartphone use is indeed ubiquitous; 88 out of 114 participants started using their smartphone as soon as they were left alone. However, the findings of this study also demonstrate great diversity in smartphone use, in e.g. social media platforms used and motivations for using different apps. These results illustrate that it no longer seems sensible to refer to “screen time” as if it represents a homogeneous phenomenon across youth. Additionally, preliminary indications have been found of relationships between individual differences in mental health indices and variations in smartphone use. The current study provides new insights into youths’ smartphone use and its relationship with wellbeing.