Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: Mattress sags a bit in the center of both sides of the bed.  Would this solve the problem?  What about 3-inch size?
Document: I feel that you should sink into the bed a little anyway I dont want a rock hard bed to sleep on at night. If this doesnt feel right in a year or so I may get the 3 or 4 inch king size in the future.
This fixed the problem I had with the middle of my mattress sagging. It only did so for 3 months until it itself had a sag in the middle of it.If you need a new mattress and are trying to delay it by purchasing this DONT! Apply the $80 to your new mattress. I purchased a AmeriSleep Americana King Size Memory Foam mattress for $950 and it is awesome!
I'm glad I got the extra firm, but I wish I would of got the 3 inch. I no longer have back aches or hip aches. That is why I love this product so much. I have a Tempur-Pedic ($3000.00) for about 5 years and my back and hip started to bother me for the past few months and I did not want to buy a new bed so, this pad worked out for me just fine.
I ordered this because my bed was really lumpy and this fixed the problem. My backpain has stopped and I'm satisfied. I was worried because the "firm" topper feels soft and cushy when you press into it, but once I lied down, it was firm and fully supportive. I'm glad I purchased this instead of a new mattress. I've used it for several months now and I think it has lost a bit of firmness, so I just flipped the topper.
We have an extra firm mattress we just bought for only $900, but our last mattress was a memory foam topper $2500 mattress. That built-in topper wore out after 5 years. This one is a good fit, almost perfect match to the king size bed. One minus I noted was it did seem to make the bed a bit hotter than normal.Overall:Its a good cheap price and does what it says it will do. I think I may need something a bit higher end though.
Bought this to help a plush top mattress that was caving in, I'd say 20% improvement. It's firm and comfortable but didn't solve the problem of the mattress.
I actually first bought the 3 inch in this topper and we were happy with it as I wrote in a review for the 3 inch, but we needed some way to slightly elevate the head of the bed and to buy the foam at a fabric store for just what we needed just wasn't worth the cost.
I bought a cheap full size bed fir an apartment I use during the week. Big mistake! The bed did nit support my back and I woke up with back problems. Once I bought the Sleep Better 2 inch, my troubles were gone and I sleep very comfortably.
Needless to say I never got a full night's sleep and I would also get severe lower back pain throughout the day during my daily tasks.Finally, my husband and I ordered this product hoping it would make our bed a bit more firm and more like the mattress we had before we moved.
This product came cut about 3" to wide and 5" to short for a twin bed.It took the most uncomfortable mattress I have ever slept on and made it into a decent bed. I would much rather have just gotten a new mattress but that option wasn't availible to me so I had to resort to this. Overall it lives up to expectations. It smoothed out overnight and filled out to the advertised 2" (or close enough to it).
Answer: Try flipping your mattress first, then if that does not work, purchase the 3 inch extra firm...