Key duplication is essential for various reasons, offering convenience, security, and preparedness. Having a spare key ensures you're not stranded in case of a lost key, and it provides an accessible solution during emergencies. Duplicate keys are often shared among family members or trusted individuals, making it convenient for everyone to access a specific space. Additionally, property managers and landlords use key duplication for maintenance purposes and to address potential lockouts. Overall, key duplication serves as a practical and preventive measure, enhancing accessibility and security in various situations.