Our mattress was only 8 years old and I had sacroiliac pain. Was it from watching the grandkids? ... Or our mattress? I purchased the Temper-Pedic ProAdapt medium and it solved my problems. My husband loves the mattress too. The medium mattress is firm, but not extremely firm.
We bought a split king. My husband has the medium mattress and I have the firm. Best sleep ever. My only complaint is getting the sheets to stay on with the sheet straps at the corners
I love this mattress. I've had a Tempurpedic mattress for almost 20 years. When we bought a split king bed, I chose a soft mattress for my side after years of the medium firmness my husband likes. I prefer to sleep on my side and I'm finally waking up without a sore shoulder. I highly recommend this mattress for any side sleeper.