2. Spacing out and mixing up lessons by teachers
What a typical college is found to do is cover one topic one day, then another topic on the next day, then the other topic on the third day. This is called massed presentation. They do not usually go back and reconsider or recycle the material.
The key here is to put the materials in front of the students days or weeks later. Weekly quizzes or bringing back materials from days ago is a great option.