I am 40 now. I had a very severe stutter as a kid. As I got older it went to severe until about my early - mod 20s, and as I learned to accept it, it now varies from mild to severe. Like you said, being stressed, tired, or sick usually makes the stutter worse. This past year has been very interesting. Ive had a very traumatic year and in certain scenarios (mostly phone calls), not only have I have been pretty severe, but I have been having immense jaw tension and have been doing a lot of jaw movements and head movements. It's something I really haven't done in the past 20 years. I guess the positive thing is that it doesn't bother me like it would have 20 years ago.