I purchased the 2.5 inch Memory Foam Topper for the double bed in my spare room, two weeks prior to the arrival of visiting Guest, expecting there would be an adequate amount of time for the topper to fully expand. The delivery was received on a hot tripple digit day. The topper felt very warm when we removed it from the box. We immediately removed the tightly wrapped cellophane and left the topper laying flat on the bed, to allow the expansion process to begin. The next day I observed the center of the topper was almost fully expanded, but the outer 6 inches, along the fold lines were still compressed to less than an 1 inch. By the third day the center was fully expanded, but the outer edges were only expanded to one and a half inches or less. We left the mattress for another week and it still never completly expanded to the full 2.5 inches. Our company arrived and we were concerned it might be uncomfortable, feeling like you are going to roll off the edge of the bed. The guest were fine to try it for one night . I said I would remove it from the bed if it felt uncomfortable. The next morning the guests reported a good nights sleep and they did not want the topper removed. After the week visit came to an end and the guests returned home, I observed the topper edges had expanded a bit more. At that point I decided to keep the topper, as it had already been used. I would not order this particular brand again. I have purchased other memory foam toppers and they have performed wonderfully. I ordered this brand because I had a double bed and there were only are few brands to choose from in this size. This one also came with a nice mattress cover, which was of good quality. I gave this a Fair rateing instead of Poor, beacuse of the mattress cover.