Here's the case: 10 is evenly divisible only by 2 and 5 (and, trivially, 1 and itself). 12 is divisible by 2, 3, 4, and 6, making it more often convenient to divide. This is why we still have 24 hours per day (often counted 1–12 twice), each divided into 60 (5*12) minutes, divided again into 60 seconds; 12 inches per foot; dozens of eggs, cookies, and doughnuts; and 360 (12*5*6) degrees in a circle, each of which is also divided into 60 minutes of 60 seconds. Prior to decimalization, a British pound was divided into 20 shillings, each of which was divided into 12 pence.I'd like to see the case for that
For units that are commonly divided, 12 is generally more convenient than 10. The only advantage to 10 is it matches the number of fingers most people have. But there are other ways to count that have historically been used by many cultures: base 20 (for fingers and toes, which also lets you divide by 4) and base 12 systems (counting the bones of your fingers, excluding the thumbs). (The Oksapmin people of New Guinea count up one arm and down the other up to 27.) The Babylonians and Sumerians used base 60, which is even more divisible than 12.
This is also why we have special names for 12 things ("a dozen") and less commonly 20 things ("a score"). We even have a special name for a dozen dozen ("a gross") and a dozen dozen dozen ("a great gross").