When evaluating a sofa lounge chair, prioritize the internal frame construction, ideally kiln-dried solid wood or reinforced steel to prevent warping. For comfort and longevity, ensure the foam density is at least 35kg/m³ (High Resilience foam). If the chair features upholstery, check the Martindale rub count; a rating of 30,000+ rubs is essential for commercial or high-traffic residential use. Additionally, verify that ergonomic angles (typically 105-110 degrees for the backrest) are integrated to provide proper lumbar support.