I'm sure my T has been cycling since I first acquired it in the summer of '09. I was feeling bad at the time and thought I had Lyme disease. My doctor found nothing, but it felt like I was poisoned by something - just odd.
For the past couple months I have been using the Mood Tracker app to help me understand the cycle and look for some pattern.
I track the T in red. Orange is my overal mood. Blue/purple is stress level and green is my carb intake.
I see know that it is about 8 days of loud ringing followed by 6 of relatively quiet, background ringing.
For people with cycling T this app may help track the ebb and flow.
I know I am lucky to get days were the ringing subsides. My heart goes out to others who are never given these days.