I've only had the mattress for a couple days.  After laying on the box spring, it was in full form within an hour...did not take long at all. There is a chemical odor that is still present, but has gotten better.  I let is air out before putting bedding for a full day but should have probably aired it out for a couple of days.  The first night was very uncomfortable because the mattress if very firm and sleeping on foam is much different from a standard pillow top mattress.  Last night I slept much better, and it seemed to conform to my body a little more but still tossed and turned. I am a side sleeper and probably should have ordered a soft mattress. Hopefully it will continue to soften up to sleep comfortably.