In the past, researchers would consider media's impact on youth in terms of three "Cs": consumption, content, and context. This article introduces a new construct--constancy--which supplants the previous terms. Constancy refers to the ubiquitous and continuous state of connected screens in the lives of children and adolescents. Constancy characterizes media content and use, which can be proactive, incidental, or contextual, exerting positive or negative effects on different users. Constancy can influence child development, as persistent access to smartphones and reception of messages will affect future generations' cognition and education, social interactions, emotions, and health. It will be important to address the developmental needs of the child or adolescent and not the smartphone in his or her pocket. Constancy requires pragmatic and innovative methodologies to understand the new circumstances around children, adolescents, and media. The landscape has changed and so must our approach to research and investigation of media effects.