As Americans worry about the potential end of a 10-year expansion, it’s worth studying the Aussies, whose winning streak is about to turn 28.

One Saturday in March, in the suburbs north of Sydney, around three dozen people gathered on a lawn outside a smallish two-bedroom apartment.

They were taking part in an idiosyncrasy of the Australian economic system. Here, selling a home tends to be an almost festive gathering, in which potential buyers show up for an auction and neighbors stop by to watch the spectacle — and quietly calibrate how much their own homes might be worth.

By Neil Irwin