We bought our bed in January of 2008. We got rid of it a year ago. I don't think they do adequate consumer testing. They should tell you not to have "relations" on these mattresses. After 2 years it was destroyed. The foam around the outside disintegrated. They wanted $400 to replace foam I can get at the craft store for less than $100. The fabric and foam under the top layer that zips off was also destroyed. These mattresses are good for couples that are celibate.
Neither of us toss and turn much, but our mattress would be half off his side of the bed by midnight (just from sleeping). We would have to get up so he could push the mattress back where it belonged.
Then there's the problem with the inflation. It never stayed where we put it. It had to be adjusted every day.
Review about: Sleep Number Bed.
Monetary Loss: $2000.