I did some when I was a kid, which didn't help much, I think. Something about breathing and maintaining eye contact. Not sure it mattered much (but with kids, it can be hard to do more complex stuff, as far as I understand). It's difficult to tell, since I wasn't in a position to monitor things. Later, as a young adult, I did some more. This turned out to be more of a self-understanding kind of thing, though. The therapist and I realized that the things I could be thinking about (with regards to my stutter) were already things I was thinking about. Apart from that, there were some rudimentary exercises that we agreed didn't help me, because I was sort of ahead of them in terms of understanding. So we never did more. But I think it was important for me to realize that my thinking was aligned with the kind of thinking that could be recommended. - And this is why I want us all to try it: Our situations are hugely different in the tiny nuances that make our individual stutter more or less unique. It's different with regards to what we bring to the table, and it's different what we can take away. The point is that we could all do with a bit of focusing, aided by a professional. It helps to be shown a direction.