7500 miles with the cheapest correct oil weight we could find. Dexos, full syn, all those other requirements didn't matter, just put the right weight in. This applied to Hertz and Avis/Budget between 2006-2018ish. Enterprise has generally been much more selective as they sell most of their cars themselves rather than just handing them back to the remarketers representing the manufacturers. They demand at least semi-syn oil, tire rotations, and then at least replace worn tires and brakes before remarketing. We did occasionally have cars kept on long term rentals well past their oil change intervals, but fudging the numbers to rent a car that had a PM due hold in the computer was a fireable offense.
So, in short, absolutely minimal for liability in not losing/writing off inventory.