I start off on my back at 80. This is pretty firm but it helps me to stretch my back out as flat as I can. I sleep like that for a couple of hours. After that I pump the mattress up to 90 or 100 and my wife rolls me to my side. I then drop the number to 55 and sleep until morning. If I feel any soreness in my hips I’ll raise and/or lower the number until it goes away.
With other mattresses and when I stay in hotels I sometimes experience a claustrophobic panic feeling from sinking too far into the mattress. With the sleep number bed I can always make it firmer or raise the head of the bed for a little while until that panic feeling goes away.