Choosing a sofa can be a daunting proposition. From cocktail parties to catnaps, it has to meet a wide variety of demands. And it’s probably the largest thing in the room, so it’s not inconspicuous.

A sofa is “among the biggest and most important pieces of furniture in the living room or family room,” said Estee Stanley, a Los Angeles-based interior designer whose celebrity clients include Ellen Pompeo, Patrick Dempsey and Justin Timberlake.

Because it is so big, and so frequently used, a sofa is not the place to experiment with trendy designs, Ms. Stanley said: “Stick with what you love, and know that you will still love it in five to 10 years.”

For different people, that means different things.

“A single guy might want to have the deepest, comfiest sofa,” Ms. Stanley said, “so all his friends can huddle together and watch football.”

But what if you have children? “A family of four might want it to be classic,” she said, “but not so precious that they have to worry when their kid smears chicken salad on it.”

• How long should a sofa be? Somewhere between seven and nine feet is usually ideal for seating three or four people, Ms. Stanley said, although she sometimes goes longer with curved sofas.

• Should it be on legs or not? It depends on the room, Ms. Stanley said, but “I love legs, so it doesn’t look as much like one big piece.”

• Which upholstery is best if you have children? Ms. Stanley sometimes uses outdoor-grade fabric from companies like Perennials and Sunbrella on indoor sofas. “My clients can’t even tell the difference,” she said. And when spills happen, “they can just wipe it down.”

SCP Tepee Sofa

Sofa with wood frame, cotton-canvas sling and feather cushions by Lucy Kurrein

From $4,040 at the Future Perfect: 212-473-2500 or thefutureperfect.com

Mags Soft Low 2.5 Seater Sofa

Deep and cushy sofa with 16-inch seat height

From $2,295 at Hay: 833-849-3025 or us.hay.com

Moet White Tufted Sofa

Button-tufted sofa with whitewashed acacia wood frame by Jannis Ellenberger

$1,999 at CB2: 800-606-6252 or cb2.com

Maxwell Sofa

Classic sofa with turned-wood legs by Maxwell Ryan

From $1,795 at Interior Define: 872-802-4119 or interiordefine.com

Auburn Sofa

Compact, flat-pack sofa

$699 at West Elm: 888-922-4119 or westelm.com

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