You can complete everything until they add new content.

Hi Mitchell,

The goal for each course is to achieve 100% course mastery, which you can do by completing the practice exercises, quizzes, unit tests, course challenges, and mastery challenges.

You can complete each of the activities as many times as necessary to achieve 100% mastery. If you re-do an activity, you will generally see different questions across each attempt, until you have already seen all of the questions in the question bank, at which point you will begin to see the same questions again.

You can learn more about the Mastery System here.

I hope this helps! Please let me know if you have any additional questions!