We bought a new mattress before hubby's back surgery, hoping that might be an easier fix (not). I let him shop/buy it since he was the guy with the aching back. All I can say is newer beds are way too TALL for me. I can no longer sit on the bed to put my socks on, I have to jump up. We've never had 'sides' of the bed so I don't notice either a sag or bump in the middle. But, I think our next mattress will likely be one you can dial-in as I like a much harder bed than Gary (now I'm the guy waking up with an ache, although once I get moving it goes away quickly). Memory foam gives me the heebie-jeebies, so that's off the table.
