[jabl]

You can actually conveniently count to 12 with one hand. Use the tip of the finger, the first and second finger joints * 4 fingers = 12. Then use the thumb as the pointer to keep track.

A base-12 number system would be advantageous because 12 is a "superior highly composite number". However, needless to say, despite the number theoretical advantages changing from our current base-10 system is essentially impossible.

[spixy]

Well you could count to 31 with one hand (5 fingers = 5 bits) and to 1023 with two hands (10 fingers = 10 bits) but not as conveniently :)