Using the U.S. Adult Training and Education Survey (N = 41,442), we examined the impact of acquiring nondegree work credentials at different ages on labor market outcomes, focusing on those close to retirement age. We examined two types of work credentials—occupational licenses and certifications. The majority of survey respondents, aged 16–66 years when surveyed, earned their most important credential, especially occupational licenses, at an early stage (before 35 years old). Although a significant share of older respondents held a work credential, fewer acquired a new credential close to retirement age. Results of multinominal logistic regression showed those obtaining a work credential close to retirement age (55–64 years old) were more likely to be in the labor force than noncredentialed respondents, but they were more likely to be underemployed or unemployed, controlling for demographic characteristics. Of those in the labor force, respondents earning a credential later (55–64 years old) were more likely to work part-time and have multiple jobs than noncredentialed respondents; those who earned a credential earlier (16–34 years old) were less likely to work part-time and more likely to work more hours weekly. Finally, among credential holders, older respondents thought work credentials earned at a younger age were more useful as a labor market signal; credentials earned later were less effective to gain or keep a job or to ensure marketability. Job-related effectiveness of occupational licenses decreased as the age when such credentials were earned increased, but certifications earned later were more likely viewed as a way to improve work skills than certifications earned at a younger age.