Extending the use of garments is often seen as an important strategy to decrease the impact of the fashion industry. However, currently there are a lack of data on and understanding of consumers’ wardrobes. This study explores consumers’ wardrobes internationally, and we aim to explore the total amount, unused and second-hand garments in order to develop interventions to support reuse. Through an online course, data were gathered in a survey about the content of participants’ wardrobes, counting the amounts of garments in predefined categories, and the amount of unused and second-hand garments thereof. Differences were found between clothing categories, age groups and gender for unused and second-hand garments. Between nationalities only differences were found for second-hand garments. These insights are supportive to targeted interventions for gender and age groups related to specific categories of (unused and second-hand) garments, to elongate the practical service life of garments, support consumers’ sustainable clothing decisions and in the end reduce consumption. Additionally, this exploration provides insights how to improve international monitoring and the value of digital wardrobe studies. Recommendations are provided, especially focused on interventions to support motivations, capabilities, and opportunities to improve reuse. Ultimately, through consumers’ wardrobes this study supports the next steps towards a more circular clothing system.