Across clinics and social media alike, simple physical tests — rising from a chair, walking a few meters, lowering oneself to the floor — have taken on an outsized cultural weight, promising glimpses into how long we might live. Experts in aging medicine are gently but firmly correcting that misreading: these assessments are diagnostic lanterns, not oracles. They illuminate where the body is struggling, and in doing so, they invite the deeper question of why — a question only a clinician, not a stopwatch, can begin to answer.