We purchased an I8 new. It was delivered and set up by Sleep Number personnel, I only watched. We set the mattresses to the initial numbers we obtained from the purchase in the Sleep Number store. We were looking for a better bed than our somewhat too soft I-Comfort. My wife has Fibromyalgia and Mixed Connective Tissue disease and develops severe muscle and back pain. The first night, she had to sleep on the couch after 1/2 hr. We changed the settings, the second night, 1 hr. It's been like that for 1 1/2 weeks. (I started to say 2 weeks, but it only seems like forever.)
My wife has had to sleep each night on the couch or the lounger, after only an hour in bed. It's too painful. We also have the SleepIQ. What a waste. It can't even tell when my fairly petite wife (5'4", 130) gets out of the bed and doesn't return. I wake up to back aches and slowly worsening pain in my left ribs. And to cap it all, after we gave it a week, trying many different setting, we called Customer Service to have them come get the bed. They refused, saying we had signed a contract to try it for at least 30 days! This is the worst bed, and the worst company I have ever dealt with.