Champ, if you've been in MA for more than 40 years you have much more time there than me but did you not ever compete, if you didn't, no problem there, but surely in tournaments you had to wear mouth guards as a minimum?
I train with a guard in a lot of the time. When I was competing regularly I would even wear it when doing non-sparing training, ie push-ups, running, so when I fought it was the norm, like not even there or an issue with breathing. That's what I would recommend to any person. Obviously you don't need this advice but anyone with issues with a guard or cup should try to just wear it always in the club or whenever (maybe not the mouth guard just walking to the shops though...) for familiarity.