I tore a disk in my back in 2008. My back never has healed to what it was. I go through mattresses like some people go through shoes. Tried every type.
Select Comfort (setting at a max. of 100% still way too soft), The firmest Temper Pedic made (got maybe a week of good sleep from it untill it started to sag).
A traditional inner spring Stearns and Foster (hard to find now), that was not all that firm and it did not take long before it started to sag.
My last bed that I gave away was a Sterns and Foster 100% latex foam bed. Again might have got 2 weeks out of it before it too started to sag. Ouch.
The one I am on now is some sort of hybrid. Part foam part inner spring. It is a Simmons. It also sags in the middle. This can't be rocket science or
brain surgery. I kept the foundation from the Temper as it is essentially a wooden platform box that does not give any. Ok so now I am looking
for an old dorm room type stuffed mattress that would essentially be one step up from sleeping on the floor. I slep well on one in college.
So far no luck. I hope all the 20 - 30 somethings that have designed these things have back problems when they get old. Then maybe they
will rethink what they are doing.