Hi chulaleo70,
When a mattress no longer relieves pressure, keeps our spine in its natural alignment in all our sleeping positions, or just doesn’t “feel” good any more … then of course there is only two possibilities. One is changes in a person (things like loss of flexibility, changes in weight, health changes, injury, changes of sleeping position, or even that “catch all” for all of us called aging :blink: ). The other possibility is changes in the mattress.
All foams will soften over time and when they do they may no longer provide the pressure relief that we need (we may “go through” the comfort layers and feel more of the firmer foam under the memory foam or other comfort materials) or they may no longer support and keep our spine in its natural alignment (which is what appears to have happened for you). How much this affects any individual will depend on where in the range they were when the mattress was new. If someone chooses a model which is close to the threshold of what they need for good alignment, then even a relatively small amount of softening may put them over their threshold even though for someone else that same mattress may last much longer because they are more in the middle of their range and can tolerate more softening.
A Tempurpedic has several inches of memory foam in the comfort layers (depending on the model) over a firmer polyfoam support core. If you turn the mattress over you will be sleeping on the support layers and these are much too firm for sleeping on. They are not a “flippable” mattress. As you mentioned this may stop some of your heavier parts from sinking in as much (such as the pelvis) and help correct the back issue … it also removes the memory foam comfort layer and will create a pressure relief issue as you are experiencing.
In general … there is little you can do when a mattress softens too much to meet your needs and preferences. A topper or mattress pad may help a bit because it will help isolate the memory foam from your body heat and it may stay a little firmer but in general a topper will tend to “follow” the soft spots in your mattress. Post #4 here has more about “firming up” a mattress that has become too soft but assuming that the issue is the mattress and not the foundation (which is the most likely) … then a “fix” for this will tend to be only partially effective and temporary at best.
There are many good options available in most areas of the country that don’t need a $2600 expenditure for a very high quality mattress whether it is memory foam or latex. If you do decide to go in the direction of a new mattress … then if you let me know the city or zip you live in i’d be happy to let you know of any of the better options I know of in your area.
The key to finding the best mattress (and there is a step by step guideline in post #10 here) is to first research the better local manufacturers and sleep shops and only then start to look for your “best” mattress.
I’m not sure how old your Tempurpedic is but they use high quality materials and tend to be very durable but if you were on the edge of your “threshold” when the mattress was new or chose a model with lower density or thicker memory foam than you really needed … then it would takes less foam softening for the mattress to become unsuitable.
Hope this helps.
Phoenix