how many times should we spray with milky water in case of powdery mildew when we are in bloom? do you have to spray with this solution every day?

Honestly, I would spray with fungicide rather than milk... Milk changes the pH of the surface of the leaf and this is SUPPOSED to help with Powdery Mildew but you've got to spray the entire surface area (top and bottom) of every leaf as well as stems and branches... and even then, the mold spores are in the air so I would assume you'd have to keep doing this for a long, long time... From what I've read, milk only helps REDUCE the powdery mildew... it doesn't eliminate it altogether. I would look for a Potassium Bicarbonate ... which is approved for organic grows and will actually kill the PM spores... there are a number of brands of this on the market.... Good luck!

and if I spray it with a fungicide, how much more effective is it than this milk method?

if a plant is more affected, should I throw it away?

do you have to spray with this solution every day? does the fungus appear again after spraying or does the infection need to disappear completely the first time? if I see powdery mildew again after spraying, should I cut that leaf?