I put my blinker on if turning at an intersection. I used to put it on when changing lanes, but after having moved to DC I stopped doing it because the second someone sees you trying to change lanes, they speed up to not let you in. DMV drivers are real a-holes. And, it's not just the "DC drivers" - the MD and VA drivers are especially guilty because most of them are commuters just trying to aggressively blast their way through traffic as quickly as they possibly can.