I have a spring mattress with a foam topper.
But I'm seriously considering getting rid of all of that and just sleeping on a few blankets directly on my plywood platform.
Discussion
You're the third person to tell me this, I have to figure out if I could sleep on such a hard surface
It takes a while to adjust. I go camping and have an inflatable, and I insulated air mattress. That's more comfy than most things to me.
I'm getting less comfy on mattresses at I loose weight.