You should SEE EVIDENCE of your students' learning EVERYDAY. Exit Slips are an excellent way to ensure that your students are reflecting on their learning as well as a way to keep tabs on their progress. I would get them to pick 2 to answer.
This set of 30 exit slips helps facilitate higher order thinking and thoughtful written response after students have reflected on a lesson or topic. Using these slips will help you collect formative assessments on your students throughout the school year