Oil change question

[SuperV8]

The only way anyone would ever tell if their oil change interval were good would be to do used oil analysis after every oil change so you can track your engine wear particles.

The use case for a particular car/engine dominates the required oil change interval. 20,000km up and down the motorway is completely different to 20,000km stop start/city driving.

Most manufactures have a caveat of 'severe use' and a list of conditions.
VAG have this list, as guidance which should be read when selecting the suitable service schedule which everyone forgets/ignores/doesn't know.

If any of these conditions apply then you shouldn't do 20+km oil changes:

Depending on 'your' use case you can change (with a diagnostic tool) the service interval from:

• Every 5,000 km/12 months
• Every 7,500 km/12 months
• Every 10,000 km/12 months
• Every 15,000 km/12 months
• Every 20,000 km/12 months
• Flexible interval
• Every 10,000 miles/12 months

Operating conditions​

In severe conditions the service intervals will be shorter
Severe conditions apply when the vehicle is operated under one or more of the following conditions:

• Frequent short trips of less than 16 km/10 miles
• Prolonged idling
• Urban driving with long idling stops
• When using fuel with a high sulphur content
• Driving in dusty, sandy or wet conditions
• Frequent driving (> 50% of the time) at sustained high speeds in high temperatures (> 32 °C)
• Frequent driving (> 50% of the time) in heavy traffic and high temperatures (> 32 °C)
• Frequent driving at temperatures below -15 °C
• Extreme temperatures