Four months for us. The 'magic' three month mark came and went without making too much of a difference, leaving me wondering was this ever going to end. But for us things did pretty magically improve when he turned four months - I still wouldn't say he's the easiest baby to wind but he doesn't suffer from it in the same way, he does tend to burp after a reasonable amount of time and actually get most of it up, and he isn't screaming with it and it isn't disturbing his sleep anymore.