Barrel Racer67 is right, you shouldn't need one all the time. It can help but probably shouldn't be permanent. The horse should learn without it at some point. Just look at the ones who have qualified at the NFR. Just how many people do you see using them? The people using them at the shows I go to have them on horses who aren't even all the way broke. These horses don't know how to use their body or feet. They look like a **** mess. Not saying that there aren't people who can use TD right, I am sure there are people using them for the right reasons.
I had no sooner said how dangerous those horses were that had the TD on and sure enough there was a serious accident and the horse ended up going one way and the rider went the other.