Decorating a living room comes with one almost universal question: sectional or sofa? Sectionals are the obvious space-saver and offer more flexibility with layout than the traditional setup of a sofa and two chair. They’re the more frugal option, too, if you employ the logic that one piece of furniture is probably cheaper than three. So why do so many of us default to the sofa?

It’s possible we’re daunted by the myriad configuration options that come with picking out sectionals, or bugged by the thought that some unlucky guest won’t have a back cushion. Or maybe it’s pure laziness: Squaring off a sofa and two chairs is easier than getting creative, after all.

Arlington designer Nicole Lanteri agrees. “The biggest misconception is that all sectionals are big, ” she said, “but if you measure the footprint and think about your layout, they actually give you more wiggle room.”

The modern sectional, which has a low, boxy frame, modular design and sleek silhouette, became popular in the 1950s during the mid-century modern movement and was popularized by Charles and Ray Eames. Although it certainly influenced style trends, it had an even greater impact on traditional furniture layouts.

While it’s gone through its share of trends over the years (remember those marshmallow-looking sofas from the ’80s?) it’s still a go-to secret weapon among designers who want to do more with less. Levin says sectionals are particularly handy for clients in small spaces who like to entertain. A sofa and two chairs can make the room feel cluttered and closed off, but a sectional lets the room breathe. The key, she said, is to make sure at least once piece of the sectional is backless.

“I almost never use sectionals in which every piece has a back because it starts to feel like house arrest, ” she said. “Keep the flow open.”

When Lanteri moved into her condo in Arlington, she wanted a sectional that offered some flexibility with layout. She bought the Lotus sectional from CB2 ($499-$799 per piece, she puts the three pieces together into a wrap-around when she has company and manages to seat eight to 10 people on it. At other times, she breaks it up into a sofa and two chairs.

These days, most mainstream retailers such as Room & Board and Pottery Barn offer sectionals that can be fully customized, from the fabric to the feet.

“People get tired of living in condos because they feel like they want more space, ” she said, “but if you buy furniture that works with you, that you can adjust to suit different occasions, like movie nights or parties, you can do a lot more with a little space.”

Once you’ve decided to take the plunge and shop for a sectional, you need to determine how much room you have to work with. Because sectionals don’t need so much breathing room, you probably have more space to work with than you think.

“Modern sectionals tend to have clean, sleek lines, ” Levin says, “and you can push them right up against the wall because the chaise usually sticks out and gives the layout some variation.”