This study investigates the long-term development of job-related affective well-being at the intra-individual level. In addition, the relationship between job resources and employee well-being was examined across time. Using a novel person-centered methodology in a sample of 402 Finnish managers, it was found that the development of favorable job-related affective well-being was eight times more probable than that of unfavorable development across the 10-year study period. Job resources predicted a high level of job-related well-being and, also, job resources increased over time along with favorable changes in well-being. Overall, the findings show that positive long-term changes in well-being are much more likely than negative changes, and that these are driven by job resources (read more).