Is the engraftment rate the most important factor in extending the duration of facial fat grafting?

I am considering fat grafting because my face lacks volume, but my biggest concern is how long the results will last. I want to get it done properly the first time so the effects last, but people around me say that getting up to a second session significantly extends the duration. I understand that the survival rate depends on the doctor's skill and ultimately determines how long the results will last. Does anyone happen to know of a place in Seoul that is famous for ensuring excellent engraftment? I am curious about the satisfaction levels of those who have actually undergone the procedure.