Wouter

A litre an hour at idle is about right for a petrol engine and it is the cheapest part of this whole thing.

Twenty years in the trade and this comes in a few times a winter. It is a non-event mechanically. What I would add to the check list: look at the coolant level as well as the oil, and listen for the fan cycling normally on the next run.

The one case that is not a non-event is a car with a known oil consumption problem, where fourteen hours can genuinely take it low enough to matter. That is why the dipstick is first on everybody's list.