DD is 4, and we currently live in fear of her waking up at night, so we don't open her door after she's down. If she's sick or something, I'll check on her, but for a typical night we're Pink Panthering up the stairs in silence and making sure the hall light is off to avoid rousing her. DH would probably have a kitten if I popped in to kiss her little cheek and she woke up.