Today's cars are pretty complicated and I've heard from numerous mechanics you can go 10K+ before an oil change. It's a marketing scam by the dealer to get you to spend money every 3850 or whatever they say. My mom had a nissan datsun back in the day and went 50 K with no oil change and nothing even happened.

 

I'd seriously doubt the knowledge of these mechanics.

 

I change my oil either/or. 3k or 3mo. I also live in Phoenix, lots of dust and with the power my car makes I abuse the oil a fair amount too.