As a teacher, data collection and analysis is something that ought to be entwined in your daily teaching. Quick check ins with your students before, during, and after a lesson. We should be collecting data as we start lessons with simple warm ups, which can inform where you begin a lesson.
Throughout the lesson you should be collecting data as well. You should be assessing as students you teach and they practice. With this you can determine which students need more support, which need to be challenged, and which are right on track.
Of course at the end of the lesson, exit tickets, individual practice and others all inform your decisions going forward.
Whether we realize it or not, data is something we use all day every day, make sure you choose your tools for assessment carefully.