Optimising retention of rural and remote primary healthcare (PHC) workers requires workforce planners to understand what constitutes a reasonable length of employment and how this varies. Currently, knowledge of retention patterns is limited and there is an absence of PHC workforce benchmarks that take account of differences in geographic context and profession. Three broad strategies were employed for proposing benchmarks for reasonable length of stay. They comprised: a comprehensive literature review of PHC workforce-retention indicators and benchmarks; secondary analysis of existing Australian PHC workforce datasets; and a postal survey of 108 rural and remote PHC services, identifying perceived and actual workforce-retention patterns of selected professional groups. Workforce-retention benchmarks that differ according to geographic location and profession can be empirically derived, facilitating opportunities for managers to improve retention performance and reduce the high costs of staff replacement.