the count bites again

renewing my car registration requires squeezing in my insurance policy number: 2 digits, 3 letters, 6 digits, a hyphen, and 6 more digits.

those last 12 digits are enough for nearly a trillion policy numbers, which means my insurer could write over 100 policies apiece for everybody on the planet, including newborn infants, without running out of numbers for several centuries.

credit cards have even longer numbers.

why do they need so many digits?