Traveled in Iceland. That was the 2nd trip to that island for me and my partner. Drove up to Akureyri in day 1st, which was about 450km drive from Keflavik airport.
A service person at the rental car company said, "this Grand Vitra is very much new (about 200km mileage at the point of rental) and really hope you can return the car with this state." No worries, I am a pretty slow driver.