Even through years of using the same coursebook, It’s always good to plan because it gives me a clear idea of procedures, timing, activities, aims, etc.
Timetable fit it’s very neccesary to link last class with the next one; and to plan ahead as well.
It depends on the groups, but it’s always very useful to prepare extra activities in case students finish earlier than expected, or some students forgot to bring the materials they were asked to, or change or arrange difficult exercises from the coursebook into easier ones.
I get confused when it comes to write a lesson plan for a long period of time, but a weekly one fits very good for me.
My coleagues work with their own styles: one makes lists of everything and brings in alot of material, when the other one makes a very good use of already existing material from the school.
Once having a very practical and simple table to follow, I can work on the lesson planning: Including objectives, materials, aims and procedures and techniques.
From the link
I found the same info as in a previows link for unit 19 where Engage, Study and Activate are three very important notions to help planning.