Just as a disclaimer, 1.5 litres remaining on a dry stick is just an estimate based on messing around with oil extractors in the past. It could be more, or less.
I'm not condoning people ignore a dry stick if they think there's still plenty of oil in the sump based off that comment
Anyway, as we all know, VW quote 1000km per litre is in tolerance, just to cover their arses because oil consumption is unpredictable. Driving style, fuel dilution and oil age since last change all affect consumption.
Mine does use some if I thrash it regularly, but driven 'normally', it barely uses anything in between 3-4K changes. I can now smell oil burning sat in traffic and I get a very small puff of blue if I rev it after 10 mins of idling, so at some point either the head or turbo will need doing, or both!
I check the oil once a week, mainly just to see how my O ring mod is holding out