Well, it is completely different from one person to another. There is no time strain for your fevs to go down to thirties. You can still keep your fevs in the 50s for 5 years who knows. Mine were in the 50s 3 years ago, but now they are in the high thirties after tune ups. I had to watch them go down slowly over that period. However, the major blow I got in my life was when I was rubbed my fevs so suddenly from the high 70s to the low 50s by just one pseudomonal infection which wasnt treated at the right time. That happened in a period of 4 months would you believe it. Anyways, as I said earlier it is not rational to predict degeneration because it depends on various factors. Goodluck, and I advise you not to worry about this stuff. Just hang on to your treatments.