As characters reach later age categories they change somewhat, generally becoming more frail as they reach their later years. This change expresses itself differently for different individuals, and while generally a negative process many characters may experience something of a silver lining by virtue of their experience.
Each time a character reaches a new age category, beyond adult they receive either a -3 age penalty split between their ability scores to be distributed as the player sees fit with a +1 age bonus to Inteligence, Wisdom, or Charisma. Alternately a character may simply take a -2 age penalty split between their ability scores distributed in the same way. Age bonuses and penalties are cumulative, they always stack.
Characters who make use of certain abilities through mental or physical exercise tend not to degenerate in these areas, as such the penalties for aging are left to the discretion of the player
Additionally with each age category a character must chose one or more age traits. Upon reaching middle age they must select one trait.
Upon reaching old age them must select two additional traits.
Upon reaching the venerable stage them must select three additional traits.
Hard of Hearing -4 to listen based perception checks, This trait may be taken multiple times but no more than once per age category
Dull Sight -4 to Spot based perception checks, This trait may be taken multiple times but no more than once per age category
Confused: Up to once per per week the character has a chance of seeing something that isn't there, the DM may describe events, creatures to the character's player that exist only in the character's mind. They also suffer a -4 penalty on sense motive checks.
Forgetful: Character has trouble remembering things, suffers a -2 penalty to all int based skill checks. This trait may be taken multiple times but no more than once per age category.
Frail: Character is easier to incapacitate, enemies may reroll confirmation rolls for critical hits.
Sickly: The character suffers from numerous chronic ailments which hamper them constanty, they suffer a -4 penalty to fort saves, and each day have a %10 chance of suffering the sickened condition.
Bad Back: The character's carrying capacity in each category is reduced by %25 of it's original value. This trait may be taken multiple times but no more than once per age category.
Cantankerous: The character suffers a -4 penalty to diplomacy, bluff, and disguise checks. NPCs who have met the character before begin each subsequent encounter one step more hostile than they would otherwise be.
Unstable: The character is not steady on their feet and prone to falls. they suffer a -4 penalty to balance checks, and to CMB when resisting being tripped or bull rushed. If this trait is taken again the penalties increase by -2 and creature who makes more than two attacks against the character in a round may, as a free action make an additional trip attack against the character. This trait may be taken only twice at seperate age categories.
Slow: The character's movement speed is reduced by 25% of its original value (round down to the nearest 5 ft.). This applies to all forms of movement the character may possess. This trait may be taken multiple times but no more than once per age category.