I purchased this mattress 12 months after having some back problems with an older cheap spring mattress i used to use. When i first got it, WOW it was fantastic, it made a massive difference and sleep was great. However after 6 months, i noticed that the mattress would not really "spring back" to its normal position, I rotated the mattress and for another 6 months this was fine. However, after that, again, dipping. The mattress is now basically F***** and i wake up with a sore neck and back due to the fact it has a huge dip it. I weigh 14 stone, hardly obese for a bloke, and my back is killing me. I will contact dreams, but from what i have read, they don't seem to do s*** all.