It’s certainly not the case that a shorter talk means shorter preparation time. President Woodrow Wilson was once asked about how long it took him to prepare for a speech. He replied: That depends on the length of the speech. If it is a 10-minute speech it takes me all of two weeks to prepare it; if it is a half-hour speech it takes me a week; if I can talk as long as I want to it requires no preparation at all. I am ready now. It reminds me of the famous quote attributed to a variety of great thinkers and writers: “If I had more time, I would have written a shorter letter.”
