I've done this quite a few times at my home airport. The closest thing we have to a "house thermal" is ridge lift on the lower slope of the ridge right next to the runway and about halfway along the downwind leg for runway 25.. There's also a helicopter operation based just off the end of that runway.. I've held there quite a few times for the helicopters and for visiting power traffic too. As I've said, staying up another five minutes as a courtesy to them doesn't cost me any extra money! The tight circuit needed at our airport frequently intimidates visiting pilots too (the base of the 6000 foot high ridge that runs along the south side of the airport is only about 400 meters from the runway so you don't get much of a base leg) so it seems considerate to give them a clear pattern if possible.