Doctors seem to love treating for perceived hypo-/hyper- thyroid conditions based solely on TSH value. But of course the best policy would be to treat based on the patient's symptoms and the free T3 and free T4 values.
My doctor wanted me to get my TSH checked every 3-4 months because he deemed the value to be too high (5.3 - 5.8 range) ... despite other thyroid hormone values being normal and being largely asymptomatic. But now that I am on Iodine and knowing it may temporarily spike my TSH I will hold off on further TSH testing for several months. I'm not in the mood for arguing with my doctor!!!