Flush the last week, every day or every other day is personal preference. I will probably be doing everyday for the last week.
I flush every 2 days with triple the size of the container of water for the last 2 weeks or so so If 5 gallon pots I use 15 gallons every 2 days
Wow, you should need to flush only once. The whole point of flushing at the end is to cleanse the soil of built-up ferts, and running 3x pot volume of water will do it. You want the plant to draw down its internal storehouse of nutes, because smoking nutes doesn't taste good. So you flush and stop feeding, to starve out the plant for the last 1-2 weeks before harvest. After the flush wait for the soil to dry out as usual before resuming regular watering as needed, no nutes but a bit of unsulfured molasses is good.