mind one's own business

Idioms  

1. Keep from meddling, pay attention to one's own affairs, as in If she would only mind her own business, there would be a lot fewer family quarrels. Already described as a wise course by the ancients (Seneca had it as Semper meum negotium ago, “I always mind my own business”), this precept has been repeated in English since about 1600.

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Example Sentences

It suggests that people are different, that one should mind one’s own business and let other people mind theirs.

From The New Yorker • May 9, 2016

One of the show’s central tensions is Jones’ competing desires to confront and flee her tormentor, a tension that boils down to the obligation to help others versus the right to mind one’s own business.

From Slate • Nov. 18, 2015

"And I think one does better to mind one's own business."

From The Trembling of a Leaf Little Stories of the South Sea Islands by Maugham, W. Somerset (William Somerset)

Thus, "One must mind one's own business if one wishes to succeed" may seem prolix and awkward, nevertheless it is the proper form.

From How to Speak and Write Correctly by Devlin, Joseph

George belonged to the old school that declared that to mind one's own business was the highest duty of man.

From Green Valley by Reynolds, Katharine