I don't weld a lot, so I still have to go through all of the checks when I do. Today I was welding and grinding. Since I have a cheater lens in my welding helmet, I was using it in grind mode to "dress up" some welds. I took a break and when I went back to welding, I found myself staring right at an arc without any shade. I've been flashed before, so I know what it's like, between low power for 16 gauge metal and luck I'm fine and not hurting tonight. After that I just went to switching between my helmet and face shield. I've got the time and it keeps me safer.
If you are going to use grind mode on you autodarkening helmet, please be diligent about switching it to weld mode when welding.
TLDR: I left my welding helmet in grind mode, struck an arc and stared right at it. Don't be a dummy like me.