I'm impressed by how often y'all checking the mirrors. I also always check when slowing or when stopped at a light, but need to check more often in traffic. I check more often on the interstate since events happen quicker and some folks like to sweep across lanes.
An example of when I should have checked.
Sitting at a stop light, waiting for a left turn arrow to enter the interstate on the way to the Jackpine Savage Rendevous two years ago, the light changes, the women in front of me is on the cell phone and doesn't notice, the car behind me honks. We all go and enter the superslab. I'm in the third lane of a four lane, she's in the second, still on the cell phone. I want to pass but figured she's distracted and don't want to chance it. Sure enough, she swerves over in front of me. In retrospect, we're going nearly the same speed and I could do nothing or better brake to increase our separation. Instead I swerve left also, however, not knowing what's in that lane and not having time to check, I split the lane, which is dangerous I know. Fortunately, there's no one there. If I had been checking mirrors, I could have changed lanes without letting it all hang out. Other things I did wrong: while trying to decide to pass her or not, I later realized I was in her blind zone. Lessons learned.
John-