Why the hair at the back specifically is the hair that gets moved.
The donor area is a band across the back of the head and the sides, above the ears.
It is not chosen at random. Those follicles are genetically resistant to DHT, the hormone behind male pattern baldness. That is why men with advanced baldness still have hair at the back.
More importantly, a follicle keeps that resistance after it is moved. Transplanted into the front, it stays resistant, and it survives.
But one thing has to be said plainly: a transplant protects the hair that was moved, not the native hair around it. If your loss is still active, that native hair can keep thinning and the area will feel less dense over time. That is why medical treatment runs alongside surgery rather than instead of it.
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.