I've started speech therapy recently, and while it's hard to see improvements, there still are. I believe that with enough practice and therapy, it's something anyone can control, even though you might not see improvements. I suggest everyone to give therapy a try if they haven't already. Answering to your questions, I don't stutter when singing but get a severe stutter when speaking languages other than my own. And regarding my life, stuttering has made speaking a challenge for me, so it tends to generate tension and insecurity when it comes to speaking. Hope that helped somehow. And I totally agree with you, it's never too late to take therapy or take different approaches towards improving stuttering.