Hi Debbie, Shampooing them about every 2-3 months is probably good unless they really need it for some reason. What I have found is that their fur, like our hair, tends to "absorb" odor. By washing their bedding on a weekly basis, and not keeping a dirty litterbox in their cage it will go a long way toward keeping them smelling pleasant. Their natural oils are very pleasant smelling, so usually unless they have gotten into something smelly or really messy they usually do better with minimal bathing. Give them a hug for me! Karla Daisy, and our "angel" Meep [Posted in FML issue 3617]