House sitting (or besitting) is the practice whereby a landlord (or "homeowner"), leaving his house for a period of time, entrusts it to one or more "house sitters", who by a mutual agreement are entitled to live there rent-free in exchange for assuming responsibilities such as taking care of the homeowner's pets, performing general maintenance (including pools, lawns, air-conditioning systems etc.), keeping trespassers off the property, readdressing the mail, and in general, making sure that everything runs smoothly just as if the owner were at home.