More recent studies, Sassler says, signal an alarm bell only for a select group: serial cohabiters. “People who live with multiple partners have higher divorce rates. If you’ve only lived with the person you are going to marry, you have no greater chance of getting divorced than a couple who hasn’t lived together,” Sassler explains.

What about the insidious tumble effect—or in the parlance of the demo, “Your lease is up, my lease is up, so, sure, let’s move in together?”

This phenomenon also needs a disclaimer, says Amanda Miller, a professor of sociology at the University of Central Oklahoma who has researched the mechanics of cohabitation. “You really have to take class into account,” Miller says. “In the research Sharon Sassler and I conducted, we found that middle-class couples were far more likely to have the luxury to decide to move in together rather than sliding into it.”