There has been more than one occasion when I have found myself in need of assistance while traveling. Sometimes that assistance may mean calling AAA or finding a hotel room for the evening. In each situation I have been happy to have funds available to cover the unexpected cost.
My most recent situation was at the very beginning of a long weekend trip to photograph sage grouse and prairie chickens. I was picking up a colleague at the airport when my low tire pressure light illuminated. Usually that means just a slow leak so I thought I could get to the airport and then assess the situation before we drove into the mountains on a spare tire. Then came that tell-tale sound - "thump, thump, thump". Yup, flat tire all right. And not only flat, but something had punctured the side-wall. It was an irreparable tire.
I called my friend, who had just landed, and told him the situation. He was extremely understanding while I waited for AAA roadside assistance (another great insurance policy to have considering the volume of driving nature and wildlife photographers do). To make a long story short, the quick trip to the airport turned into a 6 hour delay and four new tires.
Without an emergency fund I would not have been prepared to head to the mountains on dirt country roads with a spare tire. We thankfully made it to our hotel just before dark and were on our way bright and early the next morning.
We had a great weekend with lots of fantastic photos of the dancing birds, but ultimately that was because of an emergency fund.