WARNING......Physical Therapist alert......
I get this question A LOT.........mattresses and pillows......
1. For starters, everyone has different needs. The theoretical perfect is to keep the spine in alignment.
Same for pillows....
And as you would expect, mattress and pillow needs vary on your body size, shape, co-morbidities, etc.
2. The greatest benefit of Sleep Number beds is that you and your wife can have different settings. They're probably one of the best "theoretical perfect" options out there.
3. There are some cons of Sleep Number beds though. They are very expensive and most couples can do just as well going back to the 1950's and having 2 beds in a room which would be a much, much cheaper option.
Another draw back is that you can change your "number" on the fly. When it comes to activities like sleeping, the human body likes consistency. If someone is constantly playing with the firmness, it can lead to a host of aches/pains. Or, the commercial where the wife adjusts the husband's bed to stop him from snoring..........yikes, it might stop them from snoring, but then the husband wakes up with a back or neck pain.....or a headache.
4. Be wary of the memory foam folks. Memory foam mattresses often bring a "Love it or hate it" reaction. First, in general they are hot......which some love or hate. Also, as stated above, if the mattress gives too much in the wrong places, then the spine gets out of alignment which can cause problems.
For those people that move a lot while they sleep. Often the foam mattress will enable better sleep which means that you won't move as much. However, equally as often some gets worse sleep because you're stuck in a hole trying to change positions.
The reason why I say to be wary of memory foam folks is that often they sell their mattress hard. To them, getting a foam mattress was life changing and they can't understand any viewpoint to the contrary. Foam mattresses can be awesome.....but they're certainly not for everyone.
5. You body and your mattress changes over time. In general, people keep their mattress faaaaaar too long. Over time the mattress will change it's efficacy.......and you will change your body shape.