do one's homework

Idioms  

1. Be well prepared, as in Steve had done his homework before the meeting and could answer all of the client's questions. This usage transfers a school assignment to a broader context. [c. 1930]

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Example Sentences

“Nonprofits also file a 990 form with the I.R.S. It is important to do one’s homework, or have a lawyer, financial adviser or accountant work with you.”

From New York Times

“What is necessary in this situation is to do one’s homework in the countries that are in a critical situation.”

From BusinessWeek

At Dumas, that means offering sympathy that a student's parents had a fight the previous night but then insisting on the need to do one's homework anyway.

From Time Magazine Archive