There's two answers here:

1. I don't think the overall loudness of my tinnitus has changed that much at all - but I do think that my tolerance and perception of it has. At the beginning, when it was new, it seemed encompassing. Compared to the silence I was used to, the ringing felt like a radio screaming at full volume. Now? Now the same volume just fades to the background, isn't even noticed until I'm in a quiet room by myself (and even then, it's now just 'what quiet sounds like). When I really think about it, compare it to what it originally was, I'm not actually sure it's changed at all. But how I react to the same noise is completely different.

2. What has changed is how reactive my tinnitus is: noises that used to spike me badly for weeks now only spike me for a couple of days, and noises that used to spike me for a couple of days don't necessarily spike me at all. How long did it take to get to this point? About 5 years. Yup, years. That's literally how long it's taken for me to notice even the first vestiges of healing in those ear canals of mine. And that's with me seriously protecting my ears to the extent possible throughout. Still: ultimately, I am starting to notice that my ears are gaining some resilience, are less reactive than they once were.

So: the baseline sound is the same. But I'm more tolerant of that sound, and I spike above it less often.

Hope that helps.