As character's age, their abilities change as reflected in the table below (the age bands are marked up for humans, the other kindred races are listed beneath the table). When a character is created the player chooses his or her starting age, but any statistic modifications listed in that age bracket are considered to already be in place.
The modifications are cumulative as the character grows older.
In Medieval England, if a person reached their 21st birthday, their life expectancy was actually 64, therefore the DM needs to secretly generate a "life expectancy" for human player-characters once they reach their 21st nameday (although let's be honest - how many adventurers die naturally of old age?)
For other races, the life-expectancy is also generated (secretly) when they hit the lower age of the "mature" age band.
Life expectancy -
- Human = 55 + 5d6
- Dwarf = 325 + 10d6
- Halfling = 140 + 5d6
- Elf = 555 + 10d6