​Most business presentations last for about an hour. You should plan to formally present for no more than 40 minutes and leave the remaining time for questions and discussion. Discussion can take place either at the end of the presentation or at various times within it. A helpful rule of thumb is that it takes about two minutes to communicate each point within your argument.

This means that an hour-long presentation should contain no more than about 20 points, and therefore no more than 20 visuals to support your points. When it comes to presenting, less is always more.