Look over the type of legs that the furniture has. They should not be glued or nailed into place. Instead, they should be jointed into the base of the piece. They should also be made of solid wood and quite heavy. High-end sofas should have a fifth leg in the middle to support the added weight of quality.
Inspect the furniture to learn how it is built. Try to choose furniture that is constructed using wood joinery techniques. Avoid buying furniture that is held together with nails and glue. Pieces that are held together with wood joinery will hold up to more weight and for several years after the nail and glue pieces fall apart.