I think teachers should write lesson plans to stay as organized as possible. The fact that a teacher has a lesson "planned" out provides a guideline that is easy to follow. Without a lesson plan, teachers will be stuck presenting materials from off the top of their heads. Any classroom activities made for the students may not be organized. And if teachers have to spend extra time organizing the activities because they do not have a plan, then that takes away time from learning. Experienced teachers may be able to not use lesson plans only because of their familiarity with the material they are teaching. In my opinion though, lesson plans are essential even if they simple plans. The organization that lesson plans offer will save time in a classroom and keep the students more on task.
Using the lesson plans off line is a good way to gather ideas about writing your own lesson plans. However, I do not think we as teachers should copy another teacher's lesson plan and use it as our own. If my students cannot use other people's work as their own because they would be plagiarizing, then I should not another teacher's lesson plan.
http://teachers.net/lessons/posts/1144.html
