In an effort to understand the process of skill acquisition and decline, researchers have largely neglected a critical aspect of this development--maximizing time at the highest levels of achievement. This study examined length of career for professional athletes in basketball, football, ice hockey, and baseball and considers whether career length differed by position and player performance (standardized career performance). Results revealed career length differences among positions in baseball and football but not basketball and ice hockey. In all sports, longer careers were associated with superior performance, reinforcing the notion that performance is a critical indicator of career length and suggesting positional demands influence career length. Results highlight the need for further work on this important stage of development. (Contains 2 tables, 4 figures, and 1 note.)