I've traveled to many places, and once I stayed for a month in a family in Ireland. The kids there didn't change their underwear for a week. I'm not kidding!!
I even remeber that the family was so dirty, that they didn't clean the floor of the kitchen too often, and when walking on it, it sounded like *sploch* *sploch* *sploch* and my shoes used to stick to it. YUK!