Once a day or once a week, as long as you're getting practice in that's the most important thing. Like seriously, I can't even believe the amount of progress I've made over the last twelve months! I used to think I'd never be able to draw anything halfways decent and for the majority of my life I simply never tried. Then one day I said to myself "Hey, I'm going to do this thing" and it actually worked.
And yes, I definitely should draw more Ame. She's the best.