I agree with both arguments re: soundproofing a babies room. I didn't go to great lengths to be quite with my first child and he did great sleeping. He rarley woke up. But when my second came along I ran into the problem of the kids waking each other up. My 8 month old daughter is going through some teething and wakes up screaming every now and then throughout the night without warning. This usually wakes up my son in the next room and he has a hard time getting back to sleep. The next day he is tired and grumpy all day. Ensuring that he gets a good night sleep is one of my top concerns as a parent right now. And for those people who are having a hard time getting straight answers about what to do...I am with you. I am trying to at least minimize the sound that comes in and out of my kids rooms and I hear some say that insulating the walls between rooms does nothing. I hears some say that it does help. The only thing that I continue to hear is that a solid core door will help. Which I am going to try.