Just a moment...
There is a fairly well tested marketing principle that says that for your audience to understand your message well enough to act on it, it takes them hearing or seeing your message seven times.
Patty Azzarello • RISE...How to Be Really Successful at Work AND Like Your Life
This classic effect (which is even more striking when the words are printed in color) reflects the intervention of your executive control system. When the words and colors conflict, the central executive must inhibit word reading to remain focused on the task of naming the ink color.
Stanislas Dehaene • How We Learn: Why Brains Learn Better Than Any Machine . . . for Now

Writing | A Marketing Mantra for Founders
If you can’t convey verbally everything in three points, do it in seven. Also, say up front and repeatedly that there are seven points, so that when you get to the fifth one, your listeners aren’t wondering if that’s the last one or if there are 20 more.
Understandably by Bill Murphy Jr. • 7 More Things, This Time About Persuasion
Obey the seven-minute rule. This is the rule, suggested to me by a college junior, that grows out of the observation that it takes at least seven minutes to see how a conversation is going to unfold.