“A practicing Stoic will keep the trichotomy of control firmly in mind as he goes about his daily affairs. He will perform a kind of triage in which he sorts the elements of his life into three categories: those over which he has complete control, those over which he has no control at all, and those over which he has some but not complete control. The things in the second category—those over which he has no control at all—he will set aside as not worth worrying about. In doing this, he will spare himself a great deal of needless anxiety. He will instead concern himself with things over which he has complete control and things over which he has some but not complete control.”
Irvine, William B. / A Guide to the Good Life: The Ancient Art of Stoic Joy (pp. 100-101). Oxford University Press.