The dynamic development of employee health is increasingly addressed by occupational health scholarships. Based on the job demands-resources theory, this study examines reciprocal relationships among job resources, job demands, psychological capital (PsyCap), work engagement, and burnout over time. We hypothesize that PsyCap, job resources, and work engagement are part of a reciprocal gain cycle that is based on static levels and changes in these variables. Further, we assume that PsyCap has multiplicative buffering and boosting relationships with job demands and burnout. We test our hypotheses using latent change score modeling with data from 661 employees surveyed over 3 consecutive months. The results reveal a complex reciprocal cycle between PsyCap, work engagement, and job resources. However, PsyCap does not interact with the reciprocal relationship between job demands and burnout, as it is directly reciprocally related to burnout and certain types of job demands. Against the background of these results, our study contributes to research and practice on the role of personal resources, specifically PsyCap, by identifying individual differences in change patterns and highlighting the importance of considering individual differences and temporal aspects in the context of occupational health. (PsycInfo Database Record (c) 2024 APA, all rights reserved).