It's a tough life.
When I try to use the drive rack or ring out the system the people in the club just totally freak out.
Even when I warn them it's coming and it will only take a few moments of time.
It really is rare I have any feedback issues, all IEMs on stage and I use the same 6-8 presets regularly. Big problem is a new room or when I'm trying to clean up vocals. As singers voices get tired, they sometimes don't project enough and I'm riding the faders a bit to compensate..... Or, I'm bored and just playing around with effects and eq.
Funny thing is I have actually fallen asleep while mixing in the wee hours of the night. Tip, when your real tired keep your fingers OFF the faders.