The primary advantage of using a single sign-on (SSO) solution is the simplification of the user authentication process. SSO allows users to access multiple applications and services with a single set of credentials, reducing the need to remember numerous usernames and passwords. This enhances user experience and productivity while minimizing security risks associated with weak or forgotten passwords. Additionally, SSO helps organizations streamline identity management, improve compliance, and reduce the potential for unauthorized access. Overall, SSO solutions enhance both efficiency and security in user authentication.