Do mattress toppers make that much of a difference.

I would want a new mattress but I can also vouch for the mattress toppers. My mattress is foam but very firm so I added a 2inch topper. Now it's perfect. I got the topper first to lay over the dinette bed which is made up from the dinette cushions. It worked great there so I tried it on the rear bed. Then I got one for my bed at home. So I'm a believer.