Fabric is an important consideration when buying a sofa. Think about your lifestyle. If you have children and pets, look for a fabric that can withstand an extreme level of wear and tear -- so silk and linen are out. Synthetic microfiber is durable and stain resistant. Cotton, a natural fiber, can be treated for stain resistance but isn't as durable. Wool and leather can withstand extreme wear and tear, but are more costly than other fabric alternatives. Check the seams of the fabric to ensure they are well tailored. The more expensive the sofa, the better patterned fabrics will flow. At the very least, the fabric patterns should match on the front and sides of the sofa. More expensive sofas will have fabric patterns that match from the back skirt to the front skirt and on both sides.
The frame of the sofa is important to the longevity of the piece. If the frame is constructed out of a soft wood, such as pine, it is less sturdy than a frame made of ash, oak, birch or beech. Soft woods can warp after approximately five years. Kiln-dried wood -- wood with the moisture removed -- is the sturdiest frame construction material of all. While metal may seem like a good option, there's always a chance of warping. Plastic and particleboard frames don't have the lasting power of hardwoods, either. Ask the seller about frame joinery, or how the frame is put together. Frames held together by metal screws and brackets, wooden or double wooden dowels, or wooden corner blocks are good choices. Never purchase a sofa held together solely with staples, glue or nails. Legs built as part of the frame and not screwed on are preferable.
While hand-tied springs are superior, they can greatly increase the price of a sofa. Serpentine springs are a good long-lasting alternative. Push down on the sofa to make sure you feel the support. The springs should feel firm and close together. Don't purchase a sofa that contains mesh or webbing instead of springs because they won't hold up to years of use.
If you choose polyurethane foam filling, the thicker, more firm variety will prove more durable. The softer, more comfortable kind breaks down faster. High-resilient foam offers comfort and durability, but is more expensive. Down-polyfiber is economical, but flattens out with a little wear. Goose down mixed with feathers is used in high quality sofas, but you have to constantly fluff pillows. Conventional foam wrapped in polyester batting or high-resiliency foam in a layer of down can give you both comfort and durability in one. The cost will vary.