This is somewhat off topic, but here it goes:

My daily driver is an 06 Jetta (2.5 gas engine). VW's oil change interval is 10,000 miles. I'm using full synthetic Castrol.

Is 10,000 miles right or is this a subtle wa of wearing out the engine so you'll have to buy another one?

Thanks,
Konrad

That interval for full synthetic is fine, it will not even look dirty...

I still changed mine at 2,000 miles.
I only bought the oil when it was on sale somewhere.

Modern car or 914?

For a modern car running synthetic oil, follow the manual. On my 2010 fit the interval was 10K miles. On my WRX its 7000.

Zach

Non turbo modern car with synthetic? 10k

Turbo modern car with synthetic? 5k. Turbo's get the oil so much hotter that it will degrade it quicker. That and its vital to the turbo's condition that the oil stays very healthy since the shafts are lubricated with the engine oil.

The 914? Every other year or so. (about 100 miles)

Both