the number of chipped nails directly correlate with the number of miles a person travels. 

(20 freshly manicured nails + 240 miles = 17 nails without chips + 3 nails with chips = 1 nail chip per 80 miles)

real world example: had my nails done just before leaving on a trip across the planet to western australia. on the first leg of the trip, very early on, after a one hour flight to make my first connection in chicago, i noticed 2 fingernails and one toenail were already chipped.  i wondered what shape i would be in by the time i arrived in perth. 

conclusion: after 11,181 miles traveled? i considered myself lucky to have any nails at all. i’m going to go out on a limb and say that if i had been a colonial pioneer woman, traveling  across our country, in my covered wagon, clothed in calico, with my churn, 6+ children, and skinny cow, i most likely would not have been able to maintain a french manicure.