Many countries in Europe seek to increase labour force participation of older people. Previous literature regarding this issue has mainly focused on the last career stage to identify motivational forces affecting the retirement process. We propose that interventions to extend working life need to consider also young employees in order to be effective. We introduce a new construct, Expectation of Remaining in the Same Job until Retirement age (ERSJR), that is relevant for all age groups. Moreover, we suggest a Working Life Span Demands-Resources model to investigate the impact of perceived job demands and resources, as well as individual health on ERSJR. Our study is based on representative data from the German working population (N = 1586). Applying moderated multiple regression analysis we found that ERSJR is negatively related to job demands and positively to job resources and health. Resources and health interact with job demands. Analysing the model separately for different age and employment status groups we found that young blue-collar employees' expectation mainly depends on the job demands, whereas young white-collar employees only take the perceived job resources into account. Older blue-collar employees merely base their expectation on their health, whereas older white-collar employees are influenced by all three determinants. Therefore, interventions that seek to strengthen the expectation of remaining in the actual job until retirement should differentiate between blue-collar and white-collar jobs and provide different job conditions along the working life span.