My experience was that weekly sessions in my teens had no effect, but doing something only once a week won't change anything. I didn't have an SLP that specialized in stuttering, didn't get any "homework" to do every day and probably wasn't ready to put in the work either. I went to an intensive treatment for one week, and that had a massive effect, but there was no follow up and I didn't get a program to do for myself either, so it gradually went back to normal after a while. For some reason I started to stutter less after I turned 20-something, and right now it's not a big enough problem for me to do speech therapy. I truly believe speech therapy work, but you might have to try different approaches to find what works for you, and be ready to go all in. I can't remember where I read it, but studies show that after an intensive treatment program the brains of PWS works more like persons who doesn't stutter (When speaking), but if it's not maintained it reverts. Meditation and physical exercise is always great for well being and health, and I guess it probably affects stuttering to some degree. Continue with that and do speech therapy as well? :)