This study examined age-related patterns in exposure and affective reactivity to daily stressors across a 20-year time span among adults who were between 22 and 77 years old at their baseline interview. Longitudinal data from the National Study of Daily Experiences (NSDE) consisted of three bursts of eight consecutive nightly interviews of stress and affect. Analyses made use of all available data from a U.S. National sample of respondents who participated in any of the three NSDE bursts (N = 2,845; number of daily assessments = 33,688). Findings revealed increasing age-related benefits. Younger adults (<30 years) reported the highest levels of stressor exposure and reactivity, but their stress profile improved with age. Over time, adults averaged an 11% reduction in the occurrence of stressor days, and the younger adults exhibited an even steeper decline (a 47% reduction) in their levels of stressor reactivity. For people in midlife and old age, stressor occurrence continued to decrease over time, yet among adults aged 54 years or older at baseline, stress reactivity remained stable across time.