What doses of methimazole do you consider "low dose" when treating Graves' disease long-term?

"Low dose" methimazole is traditionally considered to be doses of <5-10 mg a day, but I think the definition should be 5 mg or less a day. Indeed, some patients can be controlled on 2.5 mg a day, and I have several patients with normal thyroid function who have taken 2.5 mg every other day for sever...