San Rensho 

I try not to stop, so no I don't signal stops. I try to time my riding to avoid slowing down as much as possible. When I do stop, its at a very obvious place, like a stop light or (rarely) a stop sign, where cars already expect you to stop.

Occasionally, I will signal a stop if there is something unexpected in traffic ahead that I have to slow for, but I do it mostly to warn drivers in back of whats ahead.

The only situation I could see signalling a stop is if I were making a left turn and I had to wait for oncoming traffic to clear before making the turn. Even in that situation, I would just signal a left hand turn. Instead of signalling a stop for no apparent reason, if you signal left, drivers in back of you will then know why you are stopping in the middle of the street.