I often hear this advice to make sure something gets stuck in the audience brain: tell it 3 times. I disagree. This is the approach of the (poor) teacher asking a class to recite the alphabet over and over again. Here are some better approaches:
- Tell a story that stitches the elements of your message together
- Create a memorable visual to highlight the concept
- Give them something they will never forget (see Duarte's post)
Everything is better than boring your audience with saying the same thing three times.