There's no industry standard for firmness. A soft from one manufacturer can feel like a medium from another. The label is a starting point, not an answer. What actually determines what you need:
Sleeping position. Side sleepers usually want softer, so shoulders and hips sink in and the spine stays level. Back and front sleepers usually want firmer, so the middle doesn't sag.
Body weight. A heavier person compresses a mattress further, so a medium can feel soft. A lighter person may not compress a firm mattress enough to get any pressure relief from it at all.
Whether you share it. Couples with a big weight difference often struggle to agree, and there are ways round that, including zoned mattresses and split tensions. Worth a conversation.
Existing pain. Ongoing back or joint pain is worth mentioning to your GP or physio as well as to us. We can talk about support and pressure relief. We aren't medically qualified and won't pretend to be.
