We present new evidence on the wage and mobility of young and old workers, which is difficult to explain using standard human capital theory. Instead, we propose a simple dynamic extension of the Roy model, where worker migration and wages are jointly determined at the individual level. According to this model, a higher moving cost among older workers is the main factor driving the lower mobility among this group. Because of the higher moving costs, older workers require a higher wage increase to move across regions than younger workers, a pattern that is consistent with individual-level U.S. data. We also find an interesting dynamic effect suggesting that, given a persistent labor income shock, a higher future moving cost makes workers more mobile today.