What would you recommend to monitor previously taught content to ensure students maintain their level of knowledge and understanding?

This is a great retrieval practice question. Students are going to forget, even if 100% of students know 100% of what we have taught them. The Forgetting Curve (Ebbinghaus) is like a rollercoaster! What you have learned or mastered will begin to drop away immediately. Retrieval practice is essential. Timetable or schedule things to retrieve/review. This could be included in your scope and sequence or term...