What I meant to say was, there's no guaranteed amount of effect. It's not like work or sports in that regard (and even those aren't all that automatic, but I get what you mean). "Necessary" is supposed to imply that it will hold for everyone - which was the point I was trying to make, that stutter isn't the same for everyone. Even with lots of effort and dedication, a stutterer won't be guaranteed to achieve fluency - and that's totally not their fault, and we should take care that we don't present the case otherwise. I agree that there are things we can do about our stutter - but I think it's better if we present the struggle as one of learning to _manage_ the stutter, not "overcoming" it. That way, we don't measure success via fluency, but in (let's say) perceived control. That's a different criteria.