Do We Always Use Our Turn Signal?

That all depends were I am.
Interstate driving here is a blood sport.
So there, at night, I ALWAYS use it.
During the day lane changes happen quickly and visibility is good so I know where people are at all times.
I only use a signal during the day if we are jammed up close and I need to let someone know that I want to be moving over.
Pretty please.
On the interstate I ALWAYS glance over my shoulder before changing lanes.
I don't just rely on mirrors.
How many other drivers do that, huh?

Now the question is, if you are at a traffic light in a "turn only lane", do you still have your blinker flashing.
That's the real question.