When you own a business, you work hard to build up your reputation with customers. That reputation deserves protection.
To receive trademark protection, you don't need to register. Still, registering your trademark with the United States Patent and Trademark Office (USPTO) has clear advantages, including:
Exclusive nationwide ownership of the trademark
The right to use the ® symbol to show your trademark's registered status
The USPTO's refusal to register any close variations of the trademark, which could result in competition
The right to have your trademark become indisputable after five years of continuous use
The act of putting other users on notice with public registration