How often are City Carrier Assistants (CCAs) required to work?

City Carrier Assistants (CCAs) are employed based on the operational needs of the postal service, which means their work schedule can vary. This flexibility allows them to work either part-time or full-time hours as dictated by the volume of mail, staffing needs, and other factors affecting the postal service. This arrangement is designed to ensure that the USPS can efficiently manage its delivery operations while also accommodating various staffing requirements.

In contrast, options suggesting that CCAs work only on weekends or during holidays would limit their availability and undermine the postal service's ability to respond to fluctuating mail demands. Likewise, stating that CCAs work only full-time ignores the importance of having a workforce that can adapt to varying workload levels. Therefore, the reliance on operational needs to dictate the hours worked makes the correct answer a comprehensive reflection of the CCA's role.