I see the logic, but have never purged an auger in 8+ years of using Traegers. Maybe others have issues in high humidity areas?
I have a lot of wet weather and humidity. I started out believing in even emptying the hopper cuz of it... not any more.
As far as the AUGER goes, not had a need to not once... the "heat up" cycle uses all the auger pellets so fresh hopper pellets are thru the auger and into your pot before you even add your MEAT, so I agree even tho there is 'logic' behind what's said, I personally see no reason to worry unless your rig gives you trouble.