Each contributes to the other and is a great way to leverage. They catch up on what is going on as they come in, explain things to each other, and leave when they have seen and heard enough. This approach can be surprisingly efficient and effective, and it helps students learn from each other not just from you. Every time you answer a question for a student find a way to share the question, and answer, with other students in the course AND with students taking your course in the future. Reduce lecture time, invest in discussion and assessment time.
Students learn from each other.
Faculty need to realize this fact and leverage from it. Get students to capture, reuse, and share what they learn, and then YOU use the best of what they come up with the next time you teach the course. Co-author papers with students. You get points all the way round with no down-side, and the students can do at least part of the work. Volunteer up front for certain service assignments.