At the base (ie atom) level of body function, every nutrient is a pro-oxident which means that it can donate electrons for the health of the whole.

Electrons are needed en mass by the immune system to destroy pathogens and squash free radicals. Exposure to those things varies day by day so your nutrient requirements will as well.

The body however is designed to work through times of "drought" and can build up stores for many things so as to help it survive. In addition to that it also has many ways of "making due" when ideal nutrients are absent and internal prioritizes where nutrients are most critically needed at any given point in time.

The take away is you would ideally want to provide your body enough Iodine (and every other nutrient) at a level that will meet your average needs knowing that some days you will use more than is being taken in and some days you will use less.

Its much like gas mileage in a car. You know how many miles it is to work or the store but depending on weather and traffic conditions (as well as overall health of vehicle) will have a direct impact on how much fuel is actually used for any given trip.

H2ppy,
That is such a good question. Sorry to say, it is sooo good that I don't know the answer :-(( For certain, women need far more Iodine than men. Breasts, ovaries & uterus require well over 5mg each of Iodine or else they will develop cysts, fibroids or cancer. It is a fact that Iodine kills cancers, see Cancer in this file:
http://tinyurl.com/Iodine-Kills-Cancers

I have to agree with Trapper on this subject. It is best to take too much iodine than not enough, hence Trapper suggests 100mg a day minimum. The cost differential is trivial.

Often overlooked is that even when excess iodine goes out into the urine, it is still doing a valuable service to prevent UTI's. Urinary Tract Infections afflict far more women than men, and iodine in the urine stops UTI in a short time. Ditto for Bladder infections, and inflamed bladder, another female related problem. I don't have any good testimonials (yet) on iodine curing interstitial cystitis, but I'm still confident it will help a lot.

Drugs for cystitis are obscenely expensive, upwards of $4,000 a year that I suspect are not necessary. Sooner or later, I'm sure we will get some good testimonials on this subject. I have testimonials on the bladder & cystitis, but are not as good as they could be.
http://tinyurl.com/iodine-testimonials

So yes, my opinion is to take more iodine than needed. I see no downsides and I know that my hero Trapper would suggest even more, especially in cases of iodine deficiency disease where 200+ mg are recommended.

Hope this helps,
Grizz