In 2009, a representative subsample of participants in the Health and Retirement Study (HRS: N = 5333; Age 50-101) responded to a short day reconstruction self-administered questionnaire that asked about their time and experiences on seven activities the previous day. We evaluate the quality and reliability of responses to this 10-minute measure of experienced well-being and compare the properties and correlates of three intensity-based composites reflecting mixtures of activity-linked affective experiences (Mean Activity-Positive Affect, Activity-Negative Affect, and Net Affect), and a frequency-based index, Activity Affective Complexity, that summarizes the proportion of activities that include a mixture of positive and negative affective experiences regardless of intensity. On average, older adults reported that 36% of the activities in their day provided some mixture of feelings (e.g., interested and frustrated). Regression models revealed differential associations for the four constructs of affective well-being with socio-demographic factors, physical and mental health, and proximal indicators of the day's context. We conclude that the HRS short day reconstruction measure is reliable and discuss the conceptual issues in assessing, summarizing, and interpreting the complexity of emotional experience in older adults.