Okay. My opinion is that it depends. In reality I don't think that they have a necessity to because they are always clean, perfect skin, lovely scent and the only thing that they would have to change is clothing. Also another thing... If আপনি were to drop a pound of flour over Edwards head, would his body clean itself? I think not and in that case well he would have to shower. But what I really think is that in the case of the Cullen family who decides to try to adopt a somewhat human life and to those who want to blend in the human crowd well of course they shower.
Stephenie has mentioned that on her site somwhere, that they dont have to ঝরনা cause they smell so great naturally. None than less they shower, at least the Cullens do. And if আপনি remember the Nomad's mentioned that a bath would be nice.