He who thinks he can find in himself the means of doing without others is much mistaken; but he who thinks that others cannot do without him is still more mistaken.

There are two ways to be wrong about your own necessity, and the second is worse. Believing you need nobody is a mistake that life corrects fairly quickly, usually the first time something goes wrong. Believing that nothing can proceed without you is harder to correct, because you are the last person to find out how well things ran while you were away. It also costs more, in rest not taken and work not handed on.

Test it cheaply. Leave something to somebody else this month and stay out of it entirely, and treat whatever happens as information about your actual indispensability rather than about their competence.