There are many reasons why you choose a mattress.

Apart from the suggestions above, the rule i go by is that the spine is kept in neutral when you lie down.

Therefore, A bigger person will need something firmer than someone who is slender and light.

For example, if you put a light person on a firm bed, the person will lack the weight to deform the mattress and will no doubt feel like they are sleeping on the floor. Then if you put a heavy person on a soft mattress, then they will deform it too much and they might as well be in a hammock.

For my "mismatched" couples, i tend to recommend the firmest, most apporpriate mattress for the heaviest person since it is much easier to make it softer by adding material to it - much harder to make something firmer!

I also get my patients to lie on a new bed for at least 15-30 mins to test it out - you really don't know until then. And take your pillows too since they may have to change depending on the spinal angle the new bed gives you.

All this = TIME !! Enjoy it!