A presenter should not rely on a sole method of instruction. A well-structured lecture would have more than one method of delivery. Remember that variety is necessary, but don’t go overboard.
A presenter on the other hand should not use more than two methods/techniques for presentation as this could confuse the audience and take up too much time.
The experienced lecturer/presenter will be able to look at a topic and decide on several methods that can be used independently, or in combination, for maximum benefit of the delegates.
The presenter must make the decision on which method to use of instructions based on the delegates' requirements and not on what the presenter feels like doing.