A clear lesson plan makes the teacher aware of the aims and language contents of the lesson.
It helps teachers distinguish the various stages of a lesson and see the relationship between them so that activities of different difficulty levels can be arranged properly and the lesson can move smoothly from one stage to another.
It gives teachers the opportunity to anticipate potential problems that may arise in class so that they can be prepared with some possible solutions or other options for the lesson.
It gives teachers ,especially novice teachers,confidence in class.
Raised teachers' awareness of the teaching aids are needed for the lesson.
Planning is a good practice and a sign of professionalism.
It enables the teacher to improve class timing.
Lesson plans are also an aid to continuing development.