Groot the Sphynx enjoying his bath.
One of the most common misconceptions in the breed is that they require constant bathing. This cannot be further then the truth, and over bathing your sphynx will actually result in them becoming dirtier, faster! When we overbathe them, we throw off the PH balance of the skin. Because of this imbalance, they will produce more sebum (oil) to self regulate that PH and that excess sebum is what causes them to become dirty or tacky.
A good diet, good genetics, and a clean environment will all play important roles in skin quality and cleanliness.
I bathe my sphynx once every few months (some as infrequently as once per year), including my show cats. The only time we increase the frequency is when one of them is scheduled for Animal Assisted Therapy, as previsit baths are required. :)