I don't claim to be 100% habituated, but I call myself a definite veteran of this condition, haha.
1-Do you hear your tinnitus when in a quiet room or location? And does it bother you still, or do you have peace?
Of course I hear it if I think about it. When I'm doing well and am managing my stress/health, I don't actually think about it very much; I spend a lot of time sitting in very quiet rooms reading and working and stuff like that. I definitely have awareness of it float in and out of my consciousness, but on some level that's not very much different than being aware of hunger, or that my toes are slightly too cold, or any other homeostatic quirk.
2-Can you watch TV or listen to music without tinnitus intruding all the time?
I watch a reasonable amount of TV and play video games; overall my awareness of my tinnitus will flit through my mind sometimes, but once again this is similar to any other distracting thought (again, barring times of severe anxiety/depression, which predate my tinnitus by a decade).
3-When you crossed the line from non-habituation to habituation, was it sudden or was it subtle? Or did you even notice the change?
I go through cycles of anxiety/sleep disruption/etc. When my mental health is overall impaired, then tinnitus is much more challenging than when I'm in a good state of mind. As before, I don't attribute that anxiety to tinnitus per se, as my history with challenging anxiety states is very long indeed.
4-How long did it take to become habituated? Did your tinnitus just fade into the background and that was that?
I would say that it fades in and out of my background awareness, again, based on how well I am managing my stress (and how much distress I'm in as a result of other, unrelated medical problems).
5-What % of your life, did you really get back?
That's sort of hard to put a number on. I don't go to industrial rock concerts, get staggeringly drunk or consume recreational stimulants harder than caffeine anymore, and that's all dumb stuff I did a a fair amount of in my teens/20s. Tinnitus was the thing that put a hard stop to a lot of that, but, some of it is also growing up.
In terms of things that matter to me now, I'd say 80% or more. I don't really go to concerts anymore, but I go for hikes and go to work and hang out with my wife and friends and have lots of hobbies. I ride a motorcycle.