Only ever used when jumping etc, dont use for hacking out or flatwork. Prefer to use the least amount of gadgets possible, including nosebands - just a plain cavesson.
Don't see why so many people are anti standing martingales, they are very useful. I would prefer not to use a running martingale unless essential as they do interfere with the contact.
Agree with kat. I've used standings on a couple whose heads were at stupid heights on occasion to save my face initially. Really they should be a short term measure whilst you solve the problem with schooling. Exception to that is some that require one to hunt or jump through over excitement rather than lack of schooling.
Useful as an emergency tool. I use one for Jumping and hunting as a sort of safety belt. My horse's evasion is to lift his head above the horizontal and run. He does it rarely now, but if he chose to do it out XC it could be dangerous, so it's there just in case.
I've never used a standing martingale, I only use the martingale for jumping, and I'd be concerned that a standing martingale would limit how well he could use his neck if he needed it to balance himself.
I don't use it the rest of the time, and he is ridden in a plain snaffle with a cavesson noseband with it. I'm not a gadget fan, but a running martingale has it's place in my tack room.
I use one as my new horse is sharp. Hes ok the majority of the time, in which case it doesnt come into play, but when he starts being a kn*bber it helps me keep his head out of my face As time goes on and we gel more and work on the schooling, we wont need it. But right now its a blumming useful tool to prevent black eyes and total loss of control