Everyone needs a house sitter every now and again, and it’s great if you can keep it in your family/friend circle. That way, you don’t have to pay them as much, and you trust them not to steal your belongings. And then in return, they perhaps get a little bit of pocket change and a nice change of scenery. They get to sleep in a new bed and have the house to themselves. Maybe they even get to hang out with your pets. It’s a perfect symbiosis. 

But that’s only true if both parties hold up their ends of the contract. The house sitter must fulfill their duties while being respectful of the space. No house parties, no science experiments, etc. But the house sittee (sitted? sitter recipient?) must also do their part by making sure their abode is in tip-top shape, ready to house guests. If one part of this goes wrong, the whole thing goes topsy-turvy.