When is a horse too old?

[Pedigree Ann]

If they are like Maxwell G., they can keep running until they turn 16, when racing retirement is mandatory - tracks won't take the entry. Chindi's owners decided to retire him when he couldn't compete in stakes races anymore (age 11). I remember seeing a 17 or 18yo named McCaslin place in a steeplechase race out at the Horse Park. Some horses can keep going and others can't. Some people are still healthy and vigorous at 70 and others are basket cases at 45. It's a judgment that depends on the individual's condition rather than his age.