Look for items that have a solid frame, made of kiln-dried hardwood. Frames made of oak, alder, birch, maple or high-quality hardwood plywood or marine plywood are typically very solid.
Sofas with dense polyurethane foam core are high quality. A sofa with a heavy, dense core will last longer. Higher quality furniture has core wrapped with Dacron bathing. There are other high-quality bathing options. You should spend some time researching the options.
Remember what we said about lifting the sofa? Checking the integrity and sturdiness of frames is of utmost importance. But also the type of joints will tell you more about the quality of the furniture. High grade sofas have joints that are double doweled and fitted with corner blocks that are both glued and screwed into place. Also, they have legs that are part of the frame, not just attached. Pay attention to these small details.
One important aspect of choosing a sofa is determining the right style, shape and size. Always pick a sofa after you have analyzed your room and determined the optimal height, length and depth. If you plan sleeping on your sofa (or your wife tells you to do that), you should always measure the distance between arms.
The overall length may look good, but it does not take into consideration certain dimensions, like the length of the arms. For those with little space, buying a sofa without arms is recommended. It will have a different impact and will make the room look a bit bigger.