Human hair grows, on average, six inches per year. The growth cycle can span from two to six years. This calculates to a max of 36 inches. So how do some people grow extremely long hair. Is it possibly genetics?
Go back and look at your first statement. It’s says on average. Some people have hair that grows faster, just as some have hair that grows slower. If someone has hair that grows 9 inches a year (150% of average) then after 6 years you have 54 inch length hair.
Presumably, those with the super long hair have, in addition to healthy hair (it has to last years without significant breakage) also have hair that grows faster than average.
fertilizer.
also short legs help.
Works the same with with men’s beards. Some guys can grow them long, and some can’t.
that true otherwise they’d be ZZ Crop.
And beyond a certain age, some men’s eyebrow hair embarks on a path of acceleration. And then there’s nose and ear hair.
Preach it. The hair god’s a jerk.
I have sometimes wondered what genetic advantage eyebrow, ear and nose hair is to older men.
As I’ve seen it explained, hairs fall out naturally when they hit a certain weight. for different people, that weight varies. You can let your hair grow out all you want but if your scalp only supports a light weight, then you won’t be able to get past your shoulder blades; others can get to the mid-back; yet others can go to their feet.
If you use a turban, have dreadlocks, or otherwise use some method for supporting your hair, then you will be able to grow it out a lot longer than you would otherwise be able to.
Witness, e.g., Andy Rooney et 6 even crazier al.
ETA:
how can that list be valid if it doesn’t have Pierre Salinger on it?
Holy crap:
http://www.guinnessworldrecords.com/world-records/longest-hair-%28female%29
I think I might cut my hair if it was messing my spine up:
http://www.oddee.com/item_98708.aspx
How about longest ear hair:
http://www.dailymail.co.uk/news/article-1147686/Pictured-The-man-worlds-longest-ear-hair.html
Dreadlocks at least the portions furthest from the scalp are no longer attached.
For the record, I am not on this list.
No qualities that specifically happen due to being older are a genetic advantage, because we already had our chance to make genetic copies. After a certain age, it’s only stuff breaking down or going haywire 
Do their barbers/stylists not trim those things when they get haircuts?
My eyebrows are in the very beginnings of getting wild and crazy, and when I get a haircut, I have them trim my eyebrows while they’re at it. 5 seconds later, and no wolfman look.
the reason men’s eyebrows get bushier is to attempt to provide some shading to the eye that was previously provided by forehead hair.
Anecdote!
I had my hair cut into a pixie cut on my birthday in 2013. Since then I’ve been growing it out and I’ve only had it trimmed a couple of times. I just measured and, scalp to ends, it’s about 30cm (12 inches) long. My birthday is about six weeks away, so it’s getting close to two years - I guess my hair has been growing at twice the average they give in that article.
Stops them from procreating?
Hair falling out might correlate to weight but the reason they fall out is that the hair follicle goes dormant for a period, the hair falls out, then the follicle resumes growth with a new hair.
It has nothing to do with what weight the follicle can support. A hair doesn’t weigh very much. You will discover quite quickly that if you gently pull on your hair, it doesn’t all come suddenly falling out. And the force you are using to pull is hundreds of times larger than the weight of the hair.
Just because we have it doesn’t mean there is an evolutionary advantage.