This article analyzes the domestication of WhatsApp among Argentine individuals going through young, middle, and late adulthood, drawing on 158 semi-structured interviews and a 700-person survey. Findings show variance in domestication processes related to the different life stages that users belong to. Young adults (18–34 years, in our sample) adopt WhatsApp as a taken-for-granted platform where sociability is mainly produced in groups with friends and enacted through an “always on” availability. Middle adults (35–59 years) appropriate this platform partly shaped by a constellation of work and care responsibilities. Late adults (60 years and older) find in WhatsApp a connection with younger generations in addition to age peers, while enacting less continuous modes of availability than those in other life stages. We propose that considering life stages in domestication processes contributes to unpacking broader dynamics of the social mediation of everyday life.