Received my mattress a day before Wayfair said I would, which was a pleasant surprise. I got it opened up and allowed it to expand on top of the plastic for 36 hours. It got to the full 12 by that point and I was anxious to sleep on it. It is incredibly comfortable!! I like to sleep on my back, sides, and occasionally stomach and I found this bed to be wonderful for all sleeping positions. I hope it holds up with time, but Ive been sleeping on it for four nights now and am highly satisfied.