When to Use Visual Aids
If you are considering using visual aids (such as PowerPoint slides, for example), the first question you should ask yourself is whether you really need them at all. If it is not clear that using them will make you more effective in some specific and significant way, then don’t. Similarly, if it’s not clear that a given slide will contribute to your effectiveness, delete it.
Think of the greatest speakers of all time. Their speeches moved us, enlightened us, and compelled us to action; they made us think, laugh, cry, and fight. It was not visual aids that made these speakers effective. An engaging human being will almost always be more interesting than an image on a screen. You should be the main focus of your presentation.
One case that could call for the use of a visual aid would be the presentation of a large quantity of data. Often, such information is more immediately comprehensible to the audience in the form of a chart or graph.