When you receive a YogaBed mattress, it typically takes about twenty-four to seventy-two hours for it to fully expand. After unboxing the mattress, it will begin to decompress and regain its intended shape. Many customers notice significant expansion within the first few hours, but it is advisable to allow the full duration for optimal comfort and support. Additionally, the exact time for expansion can vary based on factors such as room temperature and humidity. For the best experience, it is recommended to let the mattress air out in a well-ventilated space during this time as well. If you require more specific details or have concerns, the YogaBed website has additional information on this topic that may assist you further.