The aging process is different for each person because of differences in each organ. But generally speaking, after entering middle age, a variety of symptoms of aging appear. Fading vision, white hair, and loose teeth are the first steps. After 75, even healthy persons can't avoid rapid aging.
「老化」的歷程，固然因人、因器官而有輕重快慢的差異，但整體說來，步入中年以後，許多老化表徵就逐一出現，「視茫茫、髮蒼蒼、齒牙動搖」，是許多人意識自己「老了」的第一步。