I've been on Ther a pedic Tri-tec 2000 with wool comfort for about 9 years? It has had the sag in the middle for awhile which isn't so so bad but now its starting to
give me hip pain. I have been content enough with it though.
I'm 58, sleep alone, side sleeper who really wants to be a stomach sleeper but can't anymore. I have lower back issues with a chronic herniated disc thing. My hips are starting to bother me. I weigh about 200 lbs. I tend to sleep hot.
I have always had a thing where I hug the sides of the bed, facing out. The sides always feel better. Maybe I like sleeping on a slight uphill? Don't know what that means, if anything but thought I'd mention it.
I will be buying a full size mattress. I travel from side to side to turn over and sleep facing out a lot and if it weren't for the pets honestly I'd probably get a twin.
I will be placing it on a decent quality slatted futon frame on top of the the thin (3-4") cotton wool futon which is what the Therapedic is on. I don't feel that I need a special mattress to do this as the current mattress is not.

I tend to sleep hot so I have never investigated the memory foam thing. I also start switching sides about every half hour about 3 hours into the night. Yes I sleep like crap but I don't think or expect a mattress to solve that. I just don't want to fight a mattress when I'm trying to turn over. So unless someone has insight I think memory foam is out.

Which leaves latex and coil variants.

A long time ago on a different mattress, before toppers were widely available I got a 2" latex topper on line at a premium site. It seemed very hard and I took it off. But honestly I don't think the experience was the end of the line I just don't know how to evaluate something with so many variables that I have no experience with.

I was talking to a retailer on the phone about chairs and mentioned I would be in the market for a mattress. He mentioned Kingsdown which I had never heard of. He said they have some sort of machine you get on which tells you what kind of mattress you need. Any thoughts on that?

I don't expect something to last forever and don't mind paying for some quality.

Suggestions? (Specific better than general).

Thank you

Mary