How much hair have I had?  There are lists on the internet that explain in unsettling detail how I'll spend approximately three weeks of my life in elevators, years sleeping, and months sitting on the toilet.  Has some pathetic soul measured the speed at which hair grows?  (I understand it's not the same for everyone, but all people don't sleep the same number of hours either.)  Calculate the circumference and surface area from front to back, multiply it by follicles per square inch, then expound that over time.  I'm confident I'd have enough for a few dozen wigs by this point, if ever I let it grow out.  Then again, it would most likely be calculated in length.  Y'know, because a small intestine can stretch the length of several football fields.  So would my lifetime supply of hair extend from Memphis to Knoxville?  Further? 

To be fair, math scholars need something to do with their degrees.