An easy way to customize IKEA sofas and chairs is to purchase slipcovers. Gater uses Bemz, a slipcover company, to create customized sofa and chair covers in dozens of different colors and fabrics.

Half of Ikea’s wood-based items are made with this compressed wood chip and resin composite material, which can’t be repaired if it cracks, Oyler said. With upholstered furniture, slipcovers ...