Zach got the helmet on 2/25/13. He's done amazingly well with it. We worked up to wearing it 23 hours a day and now he only takes it off to change his clothes and for bathtime. We were really nervous the first night he slept with it on, but he only woke up once and went right back to sleep after eating. It hasn't bothered him at all really. In fact, I think it has helped his balance! He is sitting up better than ever and rolling all over the place. He is army crawling backwards and now doesn't mind if he bumps his head. We went back last week for his first follow up appointment and the Orthopedist confirmed that it is already working. His head is already rounding out in the back and the shape is changing. He goes back in 3 weeks to check it checked again.