Originally Posted by travlineasy
I'll probably go with some 4-inch memory foam in the near future ...
Be careful about investing in enough memory foam to do you berth cushions. We purchased a memory foam bed for home thinking it would help with back pain as claimed. These things are shockingly expensive.
After six months we just gave it away. By then I was sleeping on the floor to get relief for my back and my wife was in constant pain.
I asked my doctor about this and he explained that you sink into memory foam and it tends to inhibit your turning over in your sleep and that leads to muscle cramps in your back and can also aggravate disk problems. His attitude was along the lines of "yep, another memory foam problem".
We went back to a firm mattress and went back to the normal, occasional middle aged back pains
I have talked to some people who like memory foam, but a lot more who had similar problems. The majority of the "likes" have been from people under 40.
We haven't tried a memory foam topper over standard cushions. But memory foam tends to hold heat, which wouldn't be a good thing on a humid night.
As always YMMV