Very much dependent on the donor quality and actual size of the balding area. Also dependent on other factors like age, for a norwood 6 in their 50s they are likely to get a natural looking cosmetic improvement that is suited to their age but for someone in their 20s it would be unlikely
Someone balding in the norwood 5 area with an average donor should be able to to achieve a full head of hair with scalp hair alone (FUT + FUE combo that most rarely utilise), + the option of beard hair, SMP and getting some decent length to provide the illusion of density makes their hair goals very achievable for someone in that situation even with average to lesser yields over a first or second surgery. More often than not it really is just a question of money, time and desire to go through multiple surgeries unless you're a genuine norwood 6 and have a poor donor. In saying that, Joe Tillman had multiple botched surgeries, a norwood 6 pattern with an average donor with thin hair and still managed 10000 grafts (done before the implementation of some more modern techniques and usage of beneficial products like hypothermosol graft storage solutions). I know some don't like his results, personally I think it's more a design issue but no one can argue that he didn't receive a gigantic cosmetic improvement from the days that he was slick bald. Most people run out of the will and money for more surgery before they run out of grafts, unless they go to incompetent surgeons.
Diffuse has to be decided case by case, would have to ask a variety of doctors globally. Many surgeons will avoid even if they think a good result is possible as they don't want to risk their reputation over a bad result and shock loss, which is understandable. I had a lot of grafts placed into my thinning forelock however and it turned out very well.
General rule of thumb from what I see those who have a final norwood 5 pattern and average donor should still probably look to transplants and figure out if they can afford it and endure multiple procedures, those beyond that who are in their 20s or 30s are better off going down the hairpiece route, despite all the trouble that brings. Also it's all about cosmetic improvement, some people think that if you can't achieve perfection from a transplant you shouldn't get one but nothing is further from the truth.
