Is it necessary to treat subclinical hypothyroidism with a TSH below 10 or can the patient just be screened at 6 month intervals if that's what they want?

Needs to be treated. If the TSH is elevated you have hypothyroidism and that requires treatment to prevent issues such as arthritis, heart disease and muscle weakness.
TSH = 10? If your TSH is as high as 10, that's pretty significant hypothyroidism. If i were the patient, i would want an experienced endocrinologist to work with me. The frequency of re-checks depends on why i'm hypothyroid . . . And i'm guessing yours is more than "subclinical" if your TSH is 10.
Subclin hypothyroid. Treatment does not have to begin immediately. There are some circumstances when the hypothyroidism may be transient. But usually it is progressive; the TSH will continue to elevate, the ft4 will drop, and the patient will develop symptoms. If the patient becomes unreliable, severe hypothyroidism can develop which could be life threatening. The patient needs to be informed of this.
Yes. You need a sonogram to check for masses and a nuclear test for your thyroid uptake. There is no question you need medical attention and do not trust your own hesitation or anxiety and phobias which are stopping you from getting the help you need.
Patients can. Treat or not treat as they desire; it's their right. However, why have an abnormally functioning thyroid and never have any bodily process be totally normal or running at maximal efficiency. Why endanger your health when it's very simple to return your levels to normal with the proper amount of brand name T4 replacement. There are dangers to an abnormally high tsh, even mildly elevated.
Really subclinical? Subclinical is the term for someone with no symptoms of hypothyroidism. Please look at http://bit.Ly/14aneey if you have some of those symptoms it would be worth trying. It might be worth trying to find out why you are having thyroid issues- see http://bit.Ly/1ddkbiq if you do try thyroid consider natural thyroid: http://bit.Ly/1ccxy0r.
I was wrong. Hello, since i was in the minority on this issue, i decided to delve deeper. Turns out not to be so simple. Many factors can influence the decision to treat or to monitor, and i agree with the doctor who advised you to work with an endocrinologist. Here is a resource that may help: http://www.Aafp.Org/afp/1998/0215/p776.Html good luck.