Since 2020, conversational - generative AI systems have transitioned from occasional utilities to persistent, relationship-like presences in everyday life. In parallel, educational and professional environments have increasingly normalized the use of AI for writing, inquiry, planning, tutoring, and self-regulation. This conceptual paper argues that “always-on” AI assistants are increasingly experienced not merely as tools but as digital companions: systems that are continuously available, personalized, and socially legible through natural language interaction. We synthesize interdisciplinary literature across human–computer interaction, cognitive science, educational technology, psychology, and governance to examine implications for (a) cognition and skill development via cognitive offloading, (b) emotional reliance and parasocial attachment, (c) temporal norms and expectations of immediacy, (d) family and developmental contexts, (e) trust, transparency, and epistemic integrity, and (f) institutional responsibility and governance in higher education. We propose a structured research agenda (20 questions) to support longitudinal and cross-sector investigations, emphasizing autonomy-preserving design and governance frameworks that mitigate dependency while enabling beneficial augmentation.