Whatever your family calls it -- sofa, settee, divan or davenport -- it's a major investment. To get the best sit for your buck, Good Housekeeping recommends following these five steps:

Check the frame

A sturdy frame means a long-lasting sofa. Soft wood, such as pine, is low-cost, but it might warp or wobble after five years. Pricier hardwood (kiln-dried oak, ash or beech) is more durable.

Avoid frames made of particleboard, plastic or metal; they can warp and crack. Legs should be part of the frame or held on with screws or dowels -- not with glue alone.

Tip: To test frame strength, lift one front corner or leg off the floor. By the time you've raised it 6 inches, the other front leg should have risen, too. If not, the frame is weak.

Ask about joinery

Never buy a sofa that's held together solely by staples, nails or glue.

A frame with joints connected by any of the following is solidly constructed: wooden dowels, double wooden dowels, wooden corner blocks or metal screws and brackets. Staples or nails may be used for extra reinforcement.

Ask your salesperson for written manufacturer information on frame joinery.

Test the springs

Most sofas have sinuous springs -- preassembled units of snaking wire. They're nicely supportive, but they can press on the frame or sag over time.

High-end sofas often come with "eight-way hand-tied springs." They're comfy but expensive, and some experts believe they're no better than sinuous.

Feel the springs through the upholstery -- they should be close together and firm. Sofas with no springs, just webbing or mesh, are uncomfortable and flimsy.

Tip: Sit down firmly on a corner or outside edge of a sofa you're considering. Squeaks suggest that springs are incorrectly placed or hitting the frame.

Feel the fillings

Polyurethane foam is a low-cost, easy-care cushion filling. But the more durable, high-density type can feel hard, and the softer, low-density foam deteriorates more rapidly.

High-resilient (HR) foam is slightly more expensive but more comfortable and long-lasting. Polyester fiber is inexpensive, but it flattens quickly. Goose- and duck-feather fillings are comfy, but they can clump. A down-polyfiber blend is cheaper, but it flattens fast.

Tip: Two good options that are comfortable and reasonably priced are HR foam in a layer of down, and conventional foam wrapped in polyester batting.

Find tough textiles

Cotton and linen are durable winners (but watch out for loose weaves -- they can snag). They can be treated for stain resistance, but they aren't as easy to clean.

Synthetic microfiber can mimic most fabrics and is stain-resistant. Blends of natural and synthetic fibers tend to pill within a year. Wool and leather are handsome and strong but expensive. Silk is sleek but fragile. Fabrics with pat- terns woven in tend to wear better than those with printed patterns.

Tip: Ask the store for a piece of fabric larger than the usual swatch. Place it where the sofa will go. View it in natural and artificial light, and see how much you still like it after a few days.

Sofas worth considering

The Oasis -- From CB2. Velvety polyester. Starts at $799. cb2.com

The Sophia -- From Mitchell Gold and Bob Williams. Comfortably stylish. Starts at $2,330. mitchellgold.com

The Hermitage -- From Rowe Furniture. Down/feather/foam cushions. Starts at $1,100. rowefurniture.com

The Troy -- From Crate & Barrel. Extremely durable cotton twill. Starts at $1,099.crateandbarrel.com

The Notting Hill -- From Rowe Furniture. Flared arms/curvy legs. Starts at $900.rowefurniture.com