I agree, but even if I did have to replace it, say, once a decade, it would make the surgery much more likely to be a success. When you can control the restriction of blood flow using the bodies own mechanisms, shut off the immune response within that area to remove rejection, and control the pain with targeted painkillers all automatically, the chances of dying on the table go away down. Not to mention the possible benefits of controlling your perspective of time, controlling emotions, having a perfect memory, being able to experience perfect VR, being able to remotely control machines, learning instantly via a download, automated control of replacement/additional limbs, and elimination of exhaustion all make it pretty attractive.