There's a lot of factors that go into the success of speech therapy. In my opinion, based on anecdotal experience, these factors include... How committed are you to speech therapy? What effort do you put forth during the process? Is your speech therapist competent? There are a lot of different therapists out there. I would recommend making sure you see a speech language pathologist who specializes in stuttering. Most importantly, you really need to believe that you can improve your fluency. All of us have ebbing and flowing levels of fluency. Good days and bad days. I always use that as an example as to the fact that our fluency can improve just as it has gotten worse over time for some of us. I'm a big proponent of speech therapy. I had a severe stutter for more than 20 years. Never a fluent sentence. I've been fluent for more than 20 years thanks to speech therapy.