Artistry exceeds textbooks. It is an innate skill. As with many aspects of life, some are simply more gifted than others. If a doctor simply mimics a textbook plan the doctor is only an imitator. Not an artist. Mathematical guides do not assume the reality of the 3-dimensional head.
The textbook approach relies on theories of anatomy and pre-disposed distances. To create the “perfect” look. If all doctors followed a textbook template then hair transplants would never look natural. This one aspect can make the difference between a WOW result and a “good” hair transplant. The artistic skill of the doctor to recognise the small changes in bone structure. Tailor the design to the individual makes a great result.
Some of the art is to give the cosmetic effect that density is the same. This is most obvious when the hair is longer. Because it blocks the reflection of light on to the scalp. But when the hair is short or shaved this effect is lessened. Because there appears to be less density; although this is obviously not true.
Hairline planning and design is arguably the most important aspect. As it is what we and everyone first sees face to face. It is not uncommon people have a tendency to want the hairline too high or too low. As a result, this needs to be addressed for the long term benefit of the patient. The low rounded adolescent hairline will look fine on a younger man. But not match the age and facial features of an older man. The middle-aged man may fear that a hairline that is not adequately receded at the temples may seem unnaturally low for his age.