The ideal mattress firmness is one that provides enough softness to eliminate pressure points but still has great support. Usually, a firmness level in the 3-4 range (where 5 is the most firm) is appropriate for most people.
1. Soft - If you sleep on your side then a soft mattress is ideal for you. The reason for this, is that it lets your shoulder and hips sink into the mattress while supporting the rest of your body.
2. Soft Medium - Again, this is ideally suited for those who sleep on their side. If this is you, but you prefer a more firm mattress to a softer one, choose medium support.
3. Medium - Do you change position in your sleep? Do you find yourself rotating from your side to your back? Well then a medium/firm mattress may be your best option here.
4. Firm - Ideal for those who sleep on their back or on their stomach. If you sleep in either of these positions then a firm mattress would offer you just the right amount of support.
5. Extra Firm - Extra firm mattresses offer a very firm level of support and can be good for back pain or for larger people who may not be fully supported by a soft or medium mattress. They are often referred to as an orthopedic mattress.
But why does this matter?
One size fits all..
With all of this talk about mattress firmness, we can't forget about mattress support which is in fact different.