The best quality sleep comes from a mattress that maintains natural spinal alignment and distributes body weight evenly throughout the night. The essential principle is balancing comfort and support. A mattress that is too soft can cause the lower back to sink, misaligning the spine and leading to morning stiffness. A mattress that is too firm may increase pressure points, especially at the shoulders and hips, prompting frequent position changes and disrupted sleep. Medium-firm options or mattresses with targeted support zones often enhance sleep depth and continuity. Breathable fabrics, effective temperature and moisture regulation, allergen control, and durable materials that resist sagging over time also play a major role in achieving consistently restorative sleep.