The following is how I intend to handle aging, since my campaign appears as though it may span a fair amount of time.
Characters start out with an age of 20+1d4 years. Their birthday may be whatever they like, or they may be foundlings who know nothing of their origin, but for game purposes everyone's age increments up on the stroke of midnight, December 31st. For the typical human of the setting, their chronological and biological age is the same. For the wealthy, it need not be.
If one takes anagathic drugs only made in the Nyx Cluster, one can cheat the sands of time. It is 400 Credits a month for a supply. One can take a pill every day or an injection twice a month, the price and effect is the same. If one takes one's anagathics regularly, one's biological age accrues at only half the rate. At the end of the year where the drugs are taken correctly, the PC gains one year of chronological age and half a year of biological age.
This can be advantageous, as gains to Wisdom and the like are based on chronological age, whereas the creeping frailty of senescence comes from biological age.
I use a system of lifestyle costs, and the PCs can simply add 400 Credits a month to their lifestyle bill if they take anagathics. These are, obviously, beyond the means of the everyday person on the street. They are also obviously something that everyone of substance would wish to have, indeed might be desperate to have. So, it's not only a way to give the PCs extra bills and keep them greedy, it's part of the in-character explanation for why the Nyx Cluster has so much power and wealth. Between the widely available anagathic drugs and the fantastically expensive Rejuvenation Clinic, there are a lot of people who want to give them money and stay on their good side.