I bought "best mattress" but analyze: is it actually right for MY body? Map the mattress variables: firmness, support, pressure relief based on weight, sleep position, pain issues. Calculate: if I changed mattress, would pain decrease and sleep improve? Show me the mattress needs: this firmness for my weight and position. Give me the testing strategy: try different firmness levels. Include: whether expensive = better for me, how to determine optimal firmness, and when to replace.