Purchased a new S&F Reserve Med Tight Top Queen from a furniture store in July. Had previously owned a S&F from 2001 - 2008. It sagged terribly at about 8 yrs but neither the very reputable furniture company where I purchased it nor S&F honor the 10-year warranty. I did turn the mattress over as instructed. The salesperson whom I purchased my new mattress told me the new mattresses were so much more advanced and they will not sag. The new mattress was delivered at the end of August. I usually sleep in the middle but have a tendency to move a lot in bed and end up on side. I decided to go to bed on the opposite side of the mattress for a change. Needless to say that side was much firmer than the other. I am small build and low weight. I did not expect this new mattress to get somewhat saggy in less than four months. I do like being able to raise the head and feet at times, but I only raise the head slightly rather than using two pillows, I don't use it like a chair.