If you have an original low mileage car, keep a logbook of every oil change, fuel fillup, tire rotation, tire change. It can help document the use and mileage of the car over the years. If you have previous owner records, and hand them all with the car, you can document that the mileage is actual. That was a key factor in documenting the 37,000 actual miles on my '66 Le Mans. I had copies of the previous titles with actual mileage from before the car was age-exempted as well.