It's been 4 years for me and it has gotten worse. I blame exposing myself to loud noises, even when I didn't have any incident that spiked my T. I'm much more careful now. e.g.: I don't fly without protection (14 hours in a plane at 85-100 db = not good right?), I avoid discos, concerts, I carry earplugs, and a decibel meter on my iPhone.
I have always been able to sleep though, and I no longer feel anxiety. When T started I wondered if I would be able to live like this, and if it would get worse to the point of screwing up my life. Today I think of T everyday but it's curiosity, and also hope for future research developments. I still wonder if this will be worse in a decade or so but it's not a disturbing thought.
My tolerance have increased, I even wonder how I'm able to sleep with that noise in the background, but I do sleep. It's something like a leak in the roof. Not an optimal situation, but something you can live with.