Is it possible for a healthy person to keep toenail fungus in check by trimming regularly? Or would the infection be expected to have spread further without treatment.

I've searched the internet but can't find any information about the rate of progress of nail fungus.

I have had ragged white patches and vertical streaks on both large toenails for the last three years. I keep my nails trimmed close to the quick, but if I let them grow the patches reappear. They nails are also very thick in the inner edge of the toenails.