To be honest, the wife and I found ourselves constantly searching for the right "number" for ourselves but just could not for some reason. To the point where it was affecting our sleep due to waking up and messing with it in the middle of the night. For me, once I wake up, my brain won't let me go back to sleep unfortunately. That was a big battle.
The other was because I couldn't find the right number, I'd wake up with constant back pain. So we eliminated both those factors by giving the bed to my brother and bought the Tuft and Needle foam mattress and have no regrets. Most comfortable bed I've ever owned and it's a lot cheaper than a Sleep Number.