Building upon the Conservation of Resources (COR) theory, this longitudinal study examined whether job crafting behaviors (i.e. increasing structural and social job resources and increasing challenges) predict less job boredom and more work engagement. We also tested the reverse causation effects of job boredom and work engagement on job crafting and the dynamics between the three job crafting behaviors over time. We employed a two-wave, three-year panel design and included 1630 highly educated Finnish employees from a broad spectrum of occupations in various organizations. Our results indicated that seeking challenges negatively predicted job boredom and positively predicted work engagement. Seeking challenges fueled other job crafting behaviors, which, in their turn, predicted seeking more challenges over time, thus supporting the accumulation of resources. Job boredom negatively predicted increasing structural resources, whereas work engagement positively predicted increasing both structural and social resources. These findings suggest that seeking challenges at work enhances employee work engagement, prevents job boredom, and generates other job crafting behaviors. Conversely, job boredom seems to impede job crafting (download the article).