Most mail carriers—especially those in urban areas—begin as substitutes and advance to positions as regular carriers when vacancies occur. In general, the opportunities for promotion are limited. Carriers employed in city delivery service may sometimes advance to special, nonsupervisory jobs, such as carrier-technician, carrier foreman, or route examiner. In most cases, through seniority of service, carriers may anticipate assignments to preferred routes and regular periodic pay increases. Large city post offices undoubtedly have more vacancies and promotional opportunities than smaller offices.
Private delivery companies prefer to promote from within the company, so employees start with entry-level positions and advance according to job performance and education level.