For two years I showed a Quarter horse gelding in his late teens, and I always received compliments on how good he looked, handled, and behaved for his age. I think he enjoys it; he perks up when I lead him from his stall to practice showmanship patterns, and he absolutely loves the attention he gets at shows! Other than joint issues with his knees, I don't think he'll stop showing anytime soon. Even if he did retire, he's the primary horse used at a therapeutic riding center.