How to choose the right mattress firmness

The first question in a mattress search is usually 'firm or soft?'. The better question is which position you spend most of the night in.

Side sleepers need the shoulder and hip to sink a little. If the surface is too taut, the shoulder takes the pressure and the arm goes numb. A medium to plush feel is often kinder.

For back sleepers, the goal is to keep the lower back from floating. A medium-firm surface holds the natural line of the spine and eases morning stiffness.

Front sleepers usually do better on a firmer bed. On a soft surface the hips sink and the lower back arches too far.

Body weight changes the feel too. The same bed can read firm to a lighter person and balanced to a heavier one. Trying the models, or asking with your measurements, is the surest path.