Each other's houses
We go into each other's houses.
Idling on the window seat this morning, I indulged in one of my favourite activities, people watching. I observed the young couple who walked down their second floor dwelling across the street, watched her gesture repeatedly at something down the street and then cross with him over to a house across the street. 
I realized they may very well be the new owners of the house that was for sale not long ago. And so that can only mean they were visiting across the street. Chances are, they have not known the people across the street long, so this was a visit just between neighbours, hardly an obligation.
That gave my heart a lift.
It made me think yes, we do that, don't we.