Fortune-telling time of death

Why can fortune tellers accurately calculate their own death on the day when they are about to die?

Relatively speaking, fortune tellers predict that they will die earlier than some old people and doctors (Chinese and Western). Before people die, there are signs and symptoms (omitted). A careful and experienced person will feel and know the coming of time when he is dying. Great gods and masters such as Confucianism, Buddhism and Taoism, as well as eminent monks and great monks, can calculate their own death date on that day more accurately. Refers to the natural death of people. Birth means death.