Hi George. Not sure if I am of much help but I think it really depends. Mine remained quiet for 5 years to the extent that I even forgot it existed. That was until a huge stress period 2 years ago that led to a TMJD diagnosis, and unforeseen sound trauma recently. So I am back to square one with louder T. I guess if there are no exacerbating factors, tinnitus by itself should stay the same or even decrease?
The burning question for me has always been if it would become louder as I slowly develop age-related hearing loss? I think that would be my greatest fear - the slow descent into this ringing void.