At a minimum you should shower twice per day. Once in the AM so you don't go to work smelling like you didn't shower and if you live in a warm part of the world once you heat up all of those oils and body fluids you produce at night while you sleep begin to smell. Once at night before bed to remove the grime and build up of oils and body fluids you accumulated all day long and most importantly to not contribute to the contamination of your mattress and bedding covers. You will sleep better.