For the classroom, what may seem to be redundant information in a presentation, may be necessary for students with different information processing preferences.This comes back to some of the basic "instructional design" I learned early in the game: that it's important to present information in a variety of ways because each of us learns differently and has a different learning style (in addition to providing that critical repetition and reinforcement -- what Clark Quinn called "multiple representations" in his session at the eLearning Guild event: "Deeper Learning Cognitive Science and Instructional Design")
On a sidebar note: assessing your own learning style is a whole 'nother matter.
One test showed me to be a VKA learner (Visual, Kinesthetic, Auditory)...
The TIPP learning theory showed me to be Traditional Personal with a visual preference (although I was also high on the auditory scale).
It's so easy to take one of these tests and skew your own results.