It's no picnic in any sport, but aging in MMA is particularly tough. There are no reserve roles in MMA, no bench spots or designated hitter assignments to ease into. And exits don't always, or even frequently, occur with anything resembling grace.
In other words, MMA longevity is not always cause for celebration in and of itself. No, you need a special kind of person to not only do it but make it look good in the process.
But there is a silver lining for the graying fighter population, and that's the fact that experience is a huge plus in MMA.