Printed organs offer a major step towards immortality. I could take one cell from each of my organs, and use it to grow a brand new spare. I would then be guaranteed a very long life indeed, because disease or damage could be repaired fairly quickly by swapping my organs. Arteriosclerosis? New heart, no problem. Lung virus? New lungs. Cirrhosis? New liver. There'd be no chance of rejection, because they're grown from my own cells, and the cost would rapidly reduce over time from an economy of scale. However, if I had a stroke, or brain damage due to concussion, or became demented, I couldn't exactly swap out my brain. Or could I?
While if my brain were directly swapped out entirely, I would definitely be a different person, suppose only a small amount were changed at any given time. Starting with the moment that my doctor suspects that I'm developing a brain condition, I have a small amount of my brain biopsied and replaced with a printed copy of that section. This is allowed to heal and integrate back into my brain. Then a section a few inches further is biopsied and replaced, and over the course of about five years or so, every single piece is replaced. During the healing time, the neurons reestablish their connections, so at no point do I lose psychological continuity. And when the replacing is done, I have the brain of a twenty year old. If this works, then printing will make everyone immortal eventually. Well, not totally immortal, as you could still die from injuries, or if you have a brain condition that kills you in less time than it takes to replace-and-heal. But unaging and generally free of disease.
Or would you slowly lose your memory and personality over the course of the replacement?