We recently settled down after spending a total of 4 years traveling the Americas on our bikes with our children and we ate a LOT with dirt on our hands. Water was a very precious thing and we needed it inside our bodies way more than we needed clean hands, so we would sometimes go up to 3 or 4 days between hand washings. We hardly ever got sick.

Now that we've been back in the USA for 18 months, one son still sticks by the rules of the road - I swear that kid never, ever washes his hands. He goes to school and rides his bike all over tarnation and chops wood and moves rocks, but never washes his hands. He's healthy as a horse.