The career span of professional athletea is much shorter than most occupations. Do some of them not know when it’s time to hang it up?You can’t really blame an athlete for not wanting to call it quits. Most of them have been playing their game since they were kids. In some cases, it’s literally all they know. Once they hang it up, what do they have left?

Kevin Garnett of the Boston Celtics announced over the weekend that he would return to the Celtics for a sixth season — his 18th year in the NBA overall. At 36 years old, Garnett was toying with retirement during this past season. He’s not the only veteran player to stick around in his sport, though. Jamie Moyer is still pitching at 49 years old, and Juwan Howard is still bouncing around the NBA at 39.