Grow your own organs starting to appear

as in this example where they help a patient's bladder back to normalcy.
It's beginning people: 300 year lifespans are on the horizon and I for one, don't want to be the next generation eager-beaver trying to get on the career ladder when your boss could literally tread water for the next century. Makes the baby-boomer/GenXr problems pale in comparison.
Cue the intergenerational warfare scenarios... now.