Our son can open his door, so we leave it closed at night - unless it's hot out, in which case we leave it open so that the a/c can reach his bed.

Our daughter can't open her door and if she wakes up in the middle of the night and sees that it's closed, she will wail until we open it. So we usually leave it open - or at least, make sure that it's open by the time we go to bed.

Do you leave your LO's door open or closed while they sleep?