I followed the instructions of letting it sit for 48-72 hours. I was a little nervous at first about the way it looked the first day I took it out of the box however, the next day it looked much better and even better the next day! It’s super firm, cool, and comfy for me! I was definitely nervous about buying a mattress in a box that I have not tested out before buying but it worked out perfectly. My dog also loves it lol I cannot feel him get on/off or move around on the bed. overall, happy with my purchase.