You might think that acne is simply caused by bad hygiene. This is, in fact, one of the biggest myths about the condition. Breakouts begin a little deeper, in our follicles, which are the canals out of which our hair grows. Acne appears when the male hormone testosterone (in both men and women) causes these follicles to produce more oil, or sebum, than normal. As the sebum makes its way to the surface, it carries cells with it which clump together and clog the pore -- the opening through which it would usually pass and get washed away. Once the pore is plugged, a pimple begins forming and bacteria moves in, causing it to get red and inflamed.
That said, even though bad hygiene isn't the root of the problem, it's still a good idea to maintain a clean face to keep anything from clogging follicles or providing a breeding ground for bacteria.
Your best bet is to wash your face twice a day, but avoid soaps. Soaps can rob your skin of its protective barrier, and many of them have a pH higher than your skin, which can negatively alter your skin chemistry. Chemicals called surfactants in some soaps can be very harsh and irritate your face. Instead, it's best to use a gentle facial wash to clean your skin twice a day.