I to believe in flushing. Whoever says it's a waste of time has obviously never smoked unflushed grass. Especially herb grown with chemicals, that stuff NEEDS to be flushed. I think it's a different story though with organic ferts. That in my opinion, doesn't NEED to be flushed, but still should be. Have you ever smoked unflushed grass? All those chemiclas that have been building up since veg, through flower, then you smoke it? Nasty! The bud crackles, taste like shit, smells like shit. Ya, it needs to be flushed. During the last week or so of growing the plant, it probably doesn't even use anymore of the chemicals stored in the dirt and plant.