For years I've been telling my clients and audiences to group things in threes-three agenda items, three main points, three benefits.
Three is a magical number. We remember things in threes. Think about it. We experience many threes in this culture: traffic lights (red, yellow, green), nursery rhymes (three little pigs, three little bears, religion (the trinity), movies (Three Coins in a Fountain), baseball (three strikes and you're out), and even public speaking (opening, body, conclusion).
According to the American Psychological Association there is scientific evidence that customers are more easily persuaded by repetition in sets of three. To read more click here.