Mine are in the bath together twice a day!
They have a pre-bed bath every night and DS has his hair washed at night. We always use an emolient in the water (aveeno) and then DD has her eczema routine done. They have a very quick bath in the morning - literally in and out just becuase I find it easier to deal with our morning routine this way. DD gets her hair washed in the morning (every other day) because she looks like she has been dragged through a hedge backwards and has to have *something* done to it. The alternate days is just a comb through with water.
We started the twice a day when DS was small and his eczema was bad, we found that the creams were absorbed better when his skin was damp and it just became what we do in the mornings. I find it easier to stick them in the bath than to top and tail them, DD is still in nappies so needs a decent wash in the mornings and DS wets the bed now and again so needs a decent wash on those days too.
It sounds a lot, but they are water babies who love their bath, have no objection to hair washing (I can just pour water over their heads) and because we have been doing it for so long it's second nature now. The do have a shower sometimes in the morning but I find showers harder work than a quick bath!
We may need a re-think when they get older and don't want to share a bath anymore!
Laura