Continuing on the "how old is too old" thoughts, it looks like in baseball, you can keep playing until you're in your 40s. The Times looks at three examples: Roger Clemens, Randy Johnson, and Barry Bonds. Clemens, 41, is pitching away as an Astro, Johnson, 40, just had a perfect game, and Bonds, 39 (but 40 in July) is swatting almost every ball he makes contact with for a home run. The Times notes that, in baseball, there are several cases of players that perform well in their 40s. Cy Young, Warren Spahn, Jamie Moyer, Pete Rose, and Nolan Ryan all did well for at least one season in their 40s.
In the cases of Clemens, Johnson, and Bonds, their rigorous workout regimens have helped them age better. Gothamist still sticks with our last entry on this subject, when we thought that if you can still play, you should. It's the people that aren't as good that should retire. You hear that JoePa?