It's strongly believed that rocker Bono has gotten a hair transplant. It's surprising to some that he would even concern himself with plastic surgery, but we can see him clearly balding in his 30's. Since then, his hairline has remained exactly the same without any additional recession. His hair transplant effectively kept his existing hairline in tact as opposed to lowering it.
This shows Bono's hair starting to bald. It's clear that he wanted to keep the hair that he has. A conservative approach with hair transplants (and plastic surgery in general) is always best. Less is more with plastic surgery folks!