Not the extraction or the implanting — the one step you can't undo.
It is not the extraction, and it is not the implanting. The hardest step is opening the channels and designing the hairline, because it is the only step with no way back.
When the surgeon opens a channel, he is fixing, permanently: the angle of the hair, its direction, its depth, and its distance from the one beside it. The follicle will grow exactly the way the channel was made.
And a hairline is not a straight line. A natural hairline has deliberate irregularity, and its position is set by the shape of your face and your age — not by the highest point you would like to reach.
This is why two people can get the same graft count with the same technique and walk out with very different results.
What does your case actually need?
The video explains the general rule. The number that applies to you is settled after an examination — the grafts your case actually needs, not a figure quoted before we have seen you.