Service history and mileage are documented by the original dealer maintenance booklet with stamps through 1986, and thorough records from the seller's time with the car from 1987 to the present. (bringatrailer.com)
I've heard horror stories of high costs of dealer maintenance after the factory warranty is over - which it is. (autolist.com)
Typically, it's folded into scheduled dealer maintenance, but what happens when the warranty miles are used up? (automobilemag.com)