Are cohabiters different than married couples who cohabited before marriage? This study used the 2002 wave of the National Survey of Families and Households to determine how work behavior might differ for 4 relationship types: (a) cohabiters with uncertain marriage plans, (b) cohabiters with definite marriage plans, (c) premarital cohabiters who recently married, and (d) premarital cohabiters married 5 or more years (n = 638). The results are compared with differences found in overall comparisons of all cohabiters and married couples (N = 916) and were markedly different, indicating that overall comparisons do not adequately capture the range of behavior across cohabitation and marriage. Evidence of increased specialization was found in marriage, yet steep behavioral differences were not found between cohabiters with definite marriage plans and recently married couples but instead were associated with longevity in marriage. This implies that any possible causal effect of marriage on behavior may accrue with time spent married. (Contains 3 tables, 4 figures, and 1 note.)