You are exceptionally long-lived.
Benefit: Add one-half the maximum result of the character’s race’s maximum age modifier to the character’s normal middle age, old, and venerable age categories. Calculate the character’s maximum age using the new venerable number. This feat can’t lower the character’s current age category.
Special: A character can gain this feat multiple times. Its effects stack.
Source: Standard Reference Document under Open Game License v1.0a, which updated this feat originally published in the Epic Level Handbook, page 56.