If you are changing your oil every three months then you are almost certainly wasting money. You should trust the integrity of the oil change shop about as much as you would trust an 'SEO expert.' There might be good ones, but most are looking to maximize profit at your expense.
So, now he knows he's wasting money, but he doesn't know how to exit that state. Essentially, you've told him "You're doing it wrong" (in a helpful tone, to be fair).
Months is not the metric, miles is. There is a maximum amount of time you want to leave the oil in but most people should be changing it sooner than that for mileage reasons.
Follow the manual on your car. In my case that is about every 3 months based on how much I drive. My brother drives a lot more, almost 2,000 miles a month, so he does it every other month.
And if you switch to Mobil-1 oil you can bump that to 6000 miles, and yearly (but only starting from the second usage of it, i.e. the first time you use it stick with 3000 miles). The oil costs more, but you'll save money by doing less changes.
With newer cars you can go as much as 10,000 to 15,000 miles with regular oil.
Going synthetic in an older vehicle isn't always good. a small leak into the piston woudln't be a problem with regular oil, but with synthetics you have an issue.
Read the owner's manual. Are you using the type and grade of oil and filter they recommend? If you're getting your oil changed at Jiffy Lube, I can assure you that you are almost certainly not.
Is that somehow more your own fault than when, after months of ignoring the strange popups that appear when windows starts up, your virus-ridden computer finally grinds to a halt and fails to boot?
