Sand & Ash Protection + Windscreen

To answer both your inquiries at once:
For the insurance, we always take the full insurance. We’d rather pay the bit up front than deal with issues later. We just walk away when turning the car in. You can check your credit card terms, or auto insurance terms to see if you are covered for sand wind and ash damage.

For the Sat Nav, it actually was very helpful to have the device with the Icelandic spellings of locations. The little accents over the letters matter. I hadn’t thought about it ahead of time and planned to use Google Maps, but the car Sat Nav got us where we wanted to go.

I kind of agree about the insurance. For peace of mind, would like to have all kinds of insurance possible. But feel bad that the overall cost of insurance seems to be more than the rental costs.

From a rental car perspective, Iceland is a completely different animal from most other places because of the higher probability of damage to your car. Even if you are sticking to the southern section of Iceland, conditions can be surprisingly brutal. I saw cars that had been flipped off the road by wind, paint scoured off by blowing sand, and cracked windshields. Call your credit card company...some offer complete coverage for absolutely everything - my Chase Sapphire does. If you card does not, then you absolutely need to get the full insurance including all of the Iceland-specific hazards. Yes, the coverage is expensive...but the costs of repair in Iceland are very high if you have to pay out of pocket. Take detailed pictures of the car you rent before you leave the lot, and while the person you are checking out with is there with you, so you can document previous damage and are not charged for it when you return. This is a common problem there so you want to protect yourself as much as possible.