I have an older mattress (18 years, believe it or not) and have been planning to buy a new one for a while, but didn't want to make the investment yet. After reading the positive reviews on this product, decided to take the plunge. All I can say is WOW and "why the heck did I wait so long?". This product is great and has improved my bed and sleep a hundred fold. It's only been a week, but I can't imagine being without it! The smell was negligible, and it filled out to full size quickly. Just follow the directions included in the box. In any case, I'd feel 100% comfortable recommending this to someone else!