The transplanted hair does not fall out, and will stay with you all your life because the hair on the back of the scalp of a man does not fall but the front parts will be thinning and falling.
You can observe this in your father, your grandfather, uncles and friends.
The hair on the back of the scalp never falls. Because the hair on the back of the scalp is extracted and transplanted to the front of the scalp, they will never fall out. The only important thing is to have a natural looking result, and a successful operation which will make you happy all your life.