Update  I’ve had this mattress about two months.  It fully expanded by the end of the second day.  I am sleeping very well and I love it.  Again, the mattress is the firm one.  My back is so happy.   If you’re looking for a mattress that isn’t squishy at all, this is it. 

I am on day 2 of allowing the mattress to expand. It is holding steady at about 10.5 inches.  I understand this process can take up to 72 hours.  Iâm not concerned because the Wayfair customer service is excellent and I know they will address any issue.  The mattress is fantastic—firm, but not hard. It does what it should—molds to your body to provide support.  The packaging was very well done. I was able to carefully cut open the plastic without damaging the bed.  I hope the bed eventually reaches its full 12inch  thickness, but (again) know that Wayfair will
take care of it if it doesn’t.