It is up to each individual student.  We provide resource materials for each course which includes reading the materials and viewing videos.  You will have as long as you would like to review, read, and assimilate the information.  As you feel comfortable, you will complete each lesson and exam.
The one exception is that if the student has received CLC credit for the course.  In this case, all that is necessary is for the student to review the material and pass the final exam.