How does this sound?
Race: Life expectancy [general life limitation]
Human: 65 years [~110 years]
Ursus: 200 years [~400 years]
Akim: 100 [~500 years]
Doban: 180 [~200 years]
Essentially humans life a standard lifespan given they aren't high tech, but can live through to 110 years or so in ideal conditions. The Ursus tend to be survivors, living through roughly five human generations, although they can live considerably longer. The Akim are often living through to 100 or so but in ideal conditions and very well monitored healthcare, a very few may live beyond that of the Ursus. Doban generally live through to quite an old age, and only in their last 20 years do they suddenly start to suffer aging issues.
I made most of these ages based on the kind of races they are. I figure that the Akim living that long is not based as much on survival like the Ursus, but based on self-preservation (similar to that of Elves).
I like to keep the life expectancy capped at around 200 because I don't like the idea of a 50 year old acting like (or being treated like) a child, while still allowing for the rare occurances of fairly 'ancient' characters.
EDIT: I've updated the OP of this thread with information from other threads based on things that have been asked recently.
