A friend of mine works out of his house as an independent consultant. Thus he does not get paid vacation. One day when we were on a kayak trip we were camping on Outer Island in the Apostile Isles of Lake Superior, he pulled out his sat phone to check voice mail and to call his wife. I think he said it cost a dollar a minute, but we were quite a few miles out of cell range and he had clients he had to worry about. He had an external lead acid battery for it, but when you are kayaking, the weight of that is not a problem to carry.