At 3 years old, my daughter had an unusually sophisticated vocabulary.

One spring afternoon, while heading out to the car with my wife, she looked at our car and said: "Similar, but different!" It wasn't until an hour later, when they returned from the grocery, that my wife noticed someone had stolen all of the hubcaps on our car. That's when she realized what our daughter had meant.

Standing around 3 feet tall, my daughter had a different perspective on the world. Her view helped her see the situation more clearly and quickly. But I find it interesting how she processed the experience because it has implications for designers.

"Similar-but-different" is the art of deciding which elements remain the same and which change over time.

It's a key concept in design.

Similarity clarifies choices in a complex world.

"Similar" is the resemblance between elements that hold together brand identity systems, pace complex information, and cohesively connect marketing messages over time and across media.

I see businesses—familiar with their product, service, and ideas—push to make every message different in approach, style, and form. In doing so, they lose sight of their audiences, who are overwhelmed with information and choices.

For audiences to recognize you in a crowded marketplace, some elements must stay the same.

"Different" signals a change and indicates audiences should pay attention.

Businesses often miss reaching audiences because—like long PowerPoint lists—they don't want to leave anything out. If everything is included, nothing seems important.

When your strategy and goals are clear, use "different" to highlight what is essential.