I think the mileage has to be very faithful to the use, and it can never go back to zero, if the first owner got it and hasn’t driven it, it will remain zeroed, but any lap must be registered, selling or donating, if the car has been overused it will have to be having maintenance and it is the case of having to sell to the junkyard, because the car broke down for good, so be it, or if the player has sporadic use of the vehicle, the engine may wear out prematurely, and suddenly have to restore, and maybe component maintenance can come into this so you can catch up or even get a car that the previous owner didn’t service but you’re willing to spend on the car to get it in shape perfect to use again, or buy one from someone else who took care of it and all maintenance is up to date, both occasions are valid.