I am not a legal expert on this but this is my current understanding. I have heard of surgeons that do "save" some fat (frozen typically) for later injection. However, technically (again, my understanding), is that if a doctor does this they are acting as a "tissue bank". Tissue Banks have all sorts of regulation and standards, etc. So if I doctor is doing this I would really research the laws and regs in your town to see if this is a commonly accepted practice. Again, I have heard of it being done, but have never done so myself. Harvesting fat is not "that" big a procedure in the big picture so if/when my patients need more fat I simply harvest a bit more from the thigh, buttock, hip, etc.