Cars get driven minimally (less that 10K a year).
Do you do every 3K miles?
Do you do every 3 months?
Do you do when the cute little dummy in the dashboard goes on?
I'd definitely recommend 5k oil changes for Turbo cars, particularly, the older oil cooled turbos. They can chew through even synthetic pretty quickly.I agree with LTC8k6 (you really need an easier to remember name), basically. I would summarize my thoughts as: once a year at minimum, or else every 4-5k. Assuming the standard bulk 'synthetic blend' you get with an average $20-35 oil change...i.e. the lowest grade oil in wide use...recycled 'there's gotta be SOME synthetic in there' oil.
Which...isn't really terrible oil. Better than what you got out of a brand-name bottle 20 years ago.
If full synthetic, once a year is still probably a good habit to keep, or else every 7-10k depending on use (high mileage mostly-highway cars would be the ones at ~10k). Some people will try and go longer, I say meh, it's starting to get a little more risky, and with no good cost benefit. Every car should get an oil change and a decent inspection at least twice a year. And going over 10,000 miles without rotating tires is too long on pretty much anything. Some cars can set in a decent wear pattern in as little as 5-7k or so.
Read the manual; go by mileage
Doesn't this matter if you're still under factory warranty? If it says every 3k (I know) or 6 months, don't you have to at least change it every 6 months or you risk not being covered if something happens to the engine during that time? That's what I'm doing on a low mileage car (not synthetic).
As for synthetic, my trusted indy guy tells me it can even go 2 years (I do ~3k/yr mi). He was even turning away my business in saying so. I think I'm settled at 1.5 years for this next one.
