I believe it is important for a teacher to include a variety of assessments in order to observe how well the students understand a topic. A teacher can assess students by informal and formal assessment. Informal assessment is done as a quick check daily.
Formal assessments collect summative data and are normally for grades.
Each type of assessment is important and should help the teacher set up lesson plans. I believe the teacher should always be using informal assessment by walking around, during questioning, and through daily checks. This will help the teacher understand which areas of the content that the students are struggling with in order to help review. Formal assessment is taken in order to confirm that the students understand the material that has been presented to them. It can be in the form of a project, group presentation, or test, but the students are to display their understanding of the topic and that they have mastered it.