[pardoned_turkey]

The thing is, within normal, stable households, most of good hygiene practices - including hand-washing after using the restroom - are unnecessary. You already share all the microflora, and if one person brings in something contagious, you're gonna get exposed no matter what, and it's up to your immune system to save the day.

That said, these practices do matter in other settings shared with strangers, so reflexive habits are worth having for that reason alone.

[forgotusername6]

Worms. Maybe bacteria and viruses can get everywhere regardless, but larger things like worm eggs are not going to travel so easily. Washing your hands can definitely help with the reduction in transmission of worm eggs.

[thewakalix]

Exposure isn't a binary, though. It's easier for your immune system to deal with smaller quantities.