Using same-day diaries from 394 older couples in the Panel Study of Income Dynamics (PSID), this paper develops and explores several new measures of diary quality. Two overarching questions are explored: 1) How do diary quality measures reflecting the data collection process enhance understanding of time use in later life? and 2) How well do same-day diaries from couples match up in terms of husbands' and wives' reports of time spent (actively engaged) together? We found a summary measure of diary quality indicated only 13.8% of diaries were lower quality. Lower quality diaries were more likely to be obtained from older adults (ages 70+ vs. 50-69) and first (vs. second) interviews. Joint activities from diaries of lower quality were less likely than those from higher quality diaries to be matched to an activity on a spouse's same-day diary. However, such a measure did not predict time spent in common activities nor did its inclusion have any effect on predictors of time use. We also found that among activities described as joint by at least one respondent, up to 76% had a matching record in the spouse's diary. The quality of matches appeared to be quite good, with the majority of matched activities having overlapping times reported by spouses and being described as joint by both spouses. Very similar estimates of joint time were reported by husbands and wives (about 5-5(1/2) hours). Implications of findings for future methodological and substantive investigations are discussed.