Humans have a host of invisible companions: trillions of microbes, which live both inside of us and on us. Don't run to the shower just yet—keep in mind that some of these microbes may actually be your friends.

Contrary to popular belief, microbes don’t always cause disease. As Gross Science host Anna Rothschild explains in the video below, some healthy strains of skin bacteria may actually kill certain disease-causing bacteria, or train our immune systems to fight off future infections. Which makes us wonder, if some microbes are good for us, should we stop washing our hands?

The answer is “absolutely not.” Thanks to antibiotics, modern industrial living, and changes in diet, we’ve lost many of the beneficial microbes that may have become part of our immune systems during our early evolution. As such, this has opened us up to some of the less helpful ones, which can actually make us sick.

Since everyone gets a little dirty from time to time, scientists suggest practicing “targeted hygiene,” where we focus on our biggest germ targets. Since we use our hands to interact with people, animals, and nature, they are, understandably, pretty germy. So we should wash them often—and thoroughly—in order to prevent the spread of illness.

Because the jury is still out on which microbes are good or bad for us, it's best to err on the safe side by adopting this World Health Organization-endorsed six-step hand washing technique.