I bought travel insurance for the two times I went on heli trips - both of which were in early January. Given I was skiing Tahoe over Xmas both years prior to the trips, I wanted to be covered in case (god forbid) something happened locally and I injured myself and couldn't go. In my head, the insurance was more for the possibility of cancelation over injury/evacuation on the trip. I have good health insurance through my job, though if I had to get evacuated, I'm sure I would have to cover at least some of that cost.