This is a great question. Unfortunately, I am not sure I have as great an answer!
First of all, it is kind of a "use the Force, Luke!", type of situation. You have to eventually trust your own intuition and your Master's energy. I would ask the Universe at some point before a meditation and see what comes up.
I think that
years with no results would be
VERY surprising with SFQ, if done diligently. Even a year would shock me. I would say about 300 hours or 6 months with no desired results or good effects might be a litmus test for some people.
Again, although the question is good here, in your own mind, life, words energy, focus not on "what if it does't work?" But rather, on "wow, is so cool that it is working!". Just be open to change and subtle shifts in the energy.\
Depending on someone's problem, they might need more medicine. I know there are different dosages for different body weight, types, intensity of problems etc. For me, when I had a lot of pain, I did even more SFQ. Sometimes for my migraines I would do 4-6 hour days of SFQ at least once a week. It all depends on what one is willing to do and how much time one can afford (but this same energy rule applies to money, insurance, drugs, surgery, acupuncture etc). BTW, sometimes qigong and acupuncture together can be a very powerful combination, especially when it comes to yin/yang imbalances such as depression, bi-polar, anxiety etc. I know it helped me.
ANd to echo other responses, there might be other changes and healing happening before the "desired" goal. Pay attention to ALL things in your body. Not just whatever "the problem" is. If you begin to enjoy your SFQ practice, then your answer might be, "Oh, I would do about 50-100 years and then if no improvement, stop! "
