Marketing research shows that organizations tailor communication for particular customer ‘segments’, but little is known about the live design of interaction for different categories. To investigate this, we examine telephone calls to a holiday sales call-centre (for ‘seniors’) and a university admissions call-centre (for ‘young’ students). While topically different, call-takers in both datasets requested callers’ email addresses in order to progress service. Using conversation analysis, we examine how these requests were designed, where and how ‘age’ was made relevant, and how subsequent service provision was handled in a way that matched callers’ presumed age categories. Contrastive to the static notion of ‘segments’, we show how recipient design is bound up with categorial considerations while being responsive to the live unfolding of actual interaction. The article demonstrates how a comparative collection-based approach can be used to analyse the relevance of social categories in situations where this is implicit or ambiguous. (Membership categorization, customer segmentation, conversation analysis, recipient design, requests, age)*