Stress used to make all the difference for me. Though it was by no means stress that triggered it, my stutter was always random although consistent on say...my name...or the name of my company but then random in other words..stress made it last though. Stress made it worse to where i couldn't break free as in I'd go from one block to the next to the point where I was drained and tired to even try to continue. I just posted a video of what I went through, it's a 2 part video actually but basically...if you can feel like your talking in your bath tub, there goes the stress. For me it was to stop thinking about the stutter but it's hard to explain in writing so I made the video's even though it was hard to explain in them too!