Based on some research where 22 million used car transactions were evaluated the best time to sell your car is before it rolls another 10,000 on the odometer. Dealerships get the most money out of cars that are just about to roll over to the next 10K mark and tend to get more inventory for cars in that range. Buyers don’t distinguish between 60,100 and 69,900 the same way they distinguish between 69,900 and 70,100. Even thought there is only a 200 mile difference between the two numbers buyers will pay less for cars that rolled past the next 10,000 mile mark (even if it’s only by a hundred miles).
What can we learn from this irrational behavior? Try to buy your cars when they have barely passed the next 10K mark on the odometer (ask for a discount!) and plan to sell your car when it approaches the next 10K mark on the odometer (but doesn’t cross over that mark).
This over-payment effect is the strongest from the first 10,000 miles to around the 90,000 mile mark. After 90K miles buyers seem to be more rational and pay less as the miles increase.