I'm 24 now, and I've noticed my stutter improved the most when I worked a fast food job. I avoided jobs that required speaking every since I started working at 15. At the age of 23, I got a part-time fast food because I was in between jobs. I was genuinely scared to have to face my stutter so publicly. Working the drive thru and front counter was the most frustrating, stressful, but tremendously helpful experience for me. You're forced to let go of the fact you stutter; you don't have time to worry about it when you have to face a drive-thru full of customers. The first week was brutal; completely blocking and skipping on every order. But believe it or not, it improved fairly quickly. I found that because I was forced to let go of it and accept it, I wasn't focusing on it at all, which allowed me to "heal" in a way. That 6 months of work did more for my confidence in my ability to speak - fluently or not - than my 6 months of speech therapy did. I began to notice days where I wouldn't stutter all day. It blew my mind. Every one is different, but that's what made the biggest difference for me.