I basically wash my face in the morning with just water and at night with cleanser to apply moisturizer but I also shower in between so that makes it 3 times per day.
I wash my face with cleanser (Eucerin Dermo Purifyer as recommended by my derm) morning and night but if I work out at the gym I wash it again in the shower. So that makes three times. I think twice is recommended though.
Twice is enough. But shower water can be hard on your face if you don't have a filter. If you notice that the water you use is drying out your skin or causing redness, you may want to invest in a water filter.