How about male pattern baldness? Does it matter to you proudly long haired men if your hairline starts receding?
I'm probably of balding type, but I won't let that affect my hair length: let the remaining hair grow even if the crown is bald and don't bother hiding the baldness.
Biology behind the receding hairline is that free testosterone in blood is converted into dihydrotestosterone by the elevated levels of a certain hormone, which causes the hair follicles die by interfering their blood circulation ("feeding").
Hormone levels are hereditary, but the levels of free testosterone you can affect: reduce stress, eat healthy, and build efficient muscle, and your hair is likely stay intact for longer.
I've read an interesting but uncited claim in the Internet that male pattern baldness used to be fairly rare in pre-industrial Japan, but the prevalence exploded after Japan reached its modern welfare after WWII.
Makes you think.