Accumulating longitudinal evidence suggests considerable stability in employees' work-family experiences over extended periods. However, this apparent stability may mask meaningful changes that earlier research could not detect, as prior studies often lacked designs suited to capturing shocks that alter the work-family interface and relied on long measurement intervals that can miss the adaptation process. To elucidate changes in employees' work-family interface and the resources that enable adaptation, we examine the work-eldercare interface among working informal caregivers of older adults in Singapore ( = 193) during the COVID-19 pandemic using a three-wave, "shortitudinal" design (prepandemic, during lockdown, postlockdown). Growth curve modeling revealed differential trajectories across work-eldercare constructs; work-to-eldercare conflict continued to worsen over time, eldercare-to-work conflict exhibited a partial rebound pattern, work-to-eldercare enrichment was maintained over time, and eldercare-to-work enrichment showed an improvement pattern. We also uncover important variations in how (i.e., as a stable reservoir or a dynamic supply) and for whom support at work (family-supportive supervisor behaviors [FSSBs]) and family (work-supportive family [WSF]) facilitated adaptation. Beyond between-person FSSB, within-person increases in FSSB predicted favorable trajectories of all four work-eldercare experiences. Within-person WSF did not influence trajectories beyond between-person WSF. Trait resilience enhanced the benefits of between-person FSSB and WSF on initial eldercare-to-work enrichment and work-to-eldercare enrichment, respectively, whereas within-person FSSB and WSF related to the eldercare-to-work conflict trajectory only among those lower on trait resilience. (PsycInfo Database Record (c) 2026 APA, all rights reserved).