What does this objective mean?

As a teacher it is important to grow with your students. One of the most helpful things you can do as an educator is to develop and expand your teaching style and your work. By analyzing, evaluating, and revising your lesson and unit plans you are perfecting your work in the classroom from experience in order to meet each students individual needs as a learner. 

Why is this objective important to teachers?

By allowing yourself time to analyze and revise lessons, you are ultimately helping each student succeed in your classroom. Regardless of how well a lesson goes the first time, there is always room for change. Whether that change comes in the form of creating different activities, altering vocabulary terms, or having a stronger conclusion; you as a teacher will be providing a better classroom experience for all of your students due to this change from past experience and augmentation.