I always use them when in town or heavy traffic. Now if I'm out on the interstate and their is plenty of room between vehicles I don't always use them but I also don't just cut right in front of people either. I used to drive a log truck and remember how I felt when people would do that to me.
As other drivers drive, I am wondering if turn signals are an option now on cars instead of standard. I will always let someone in if they just will let me know what they want. I think its safer that way.