Each September 21st, the world turns its attention to Alzheimer's disease — but this year, the gaze has shifted from mourning what is lost to asking what might be preserved. Researchers and clinicians are quietly reframing dementia not as an inevitable destination, but as a condition that may be shaped, delayed, or even prevented through choices made long before any symptom appears. The science is still unfolding, yet its implication is profound: the ordinary texture of a life — how one moves, eats, sleeps, connects, and thinks — may be the very architecture of cognitive fate.