It's always there, but that doesn't mean one constantly hears it. I'm listening to music a lot, so then I don't hear it. When I skateboard or do any other sports I don't hear it, et cetera. Only when it's quiet I sometimes become aware of it, but because of habituation I usually unconsciously ignore it just as quickly. It does happen that sometimes in bed I keep focusing on it to the point it annoys me, but fortunately that's rare. Not being able to experience absolute silence in a forest anymore disappoints me though; c'est la vie.

That being said, I'm probably in the camp of people whose condition is mild. It must indeed be horrible for people whose tinnitus overpowers all other sounds.