Re: Brother/sister baths
DD and DS1 bathed together until they were about 2 and 4, IIRC. A that point, DS2 was getting baths in the big tub and we did the boys together, DD got her own bath.
DS3 hasn't had many baths with the others, they're all old enough to have their own and they prefer showers anyways. Actually, DS3 all ready prefers showers himself.