Question for the SLPs that might be here.

Question for the SLPs that might be here. What are some of the factors that help or prevent people with stuttering from achieving significant improvements in their fluency? I believe I understand what allowed me to become fluent after years of severe disfluency. But I'm not (at all) educated when it comes to speech and language pathology. Everything I know is either anecdotal or what I gather from this forum and various papers I've read. I'm open to the idea of my own bias clouding my understanding of my journey to fluency.