Synthetic or conventional oil? The verdict is finally in

If you're a good car owner and follow a reasonable maintenance schedule, you most likely change your oil at least twice a year.

This has always been my practice. Scrupulous drivers do it more often, using the traditional "every 3,000 miles" rule. And so do drivers who run their vehicles hard.

But a big question comes up when undertaking this basic task, either yourself or at a professional garage or oil-change location: traditional or synthetic oil?

There are two considerations when making that call: cost and quality. Everybody knows synthetic costs more. But is it worth it?

AAA conducted an extensive scientific analysis to find out. The results, published earlier this month, aren't shocking, but they could guide consumer behaviour toward spending a bit more money to get a long-term review.

Synthetic is better. A lot better.

"Synthetic oil outperformed conventional oil by an average of nearly 50 per cent in its independent evaluation, offering vehicles significantly better engine protection for only $US5 more per month when following a factory-recommended oil change schedule," the organisation said in a statement.

In the study, AAA found that "synthetic engine oils performed an average of 47 per cent better than conventional oils in a variety of industry-standard tests," John Nielsen, the organisation's managing director of automotive engineering and repair, said in a statement.

"With its superior resistance to deterioration, AAA's findings indicate that synthetic oil is particularly beneficial to newer vehicles with turbocharged engines and for vehicles that frequently drive in stop-and-go traffic, tow heavy loads or operate in extreme hot or cold conditions."

A lot of drivers already kind of knew that. I did, but there have been plenty of times when I opted for "dinosaur oil" over the higher-tech and pricier synthetic stuff.

AAA was quite honest about the findings. You aren't going to hurt your engine if you skip the Mobil 1, one of the best-known synthetics. But you aren't going to put yourself in the poorhouse if you flip for the synthetic, either -- these oils add only $US64 a year on average to vehicle-operation costs.

You might think you're being upsold at the oil-change place. But the upsell pays off for you and the mechanic.

AAA didn't go light on the research. The report it produced is a deep dive into these lubrications.

"AAA's engine oil research focused on eight industry-standard ASTM (American Society for Testing and Materials) tests to evaluate the quality of both synthetic and conventional engine oils in terms of shear stability, deposit formation, volatility, cold-temperature pumpability, oxidation resistance and oxidation-induced rheological changes," the organisation said.

I've been opting for synthetic for a few years now because I figure it would cover me better than changing the oil more often.

It is important to remember that you don't need to go synthetic if cost is an issue -- that's the catch. When my 1998 Saab 900S was on its last legs, I went back to conventional for oil changes. I wasn't going to deprive myself of a decent bottle of wine for that jalopy, which I loved but had to send to its final reward when I moved back East a few years ago.

However, if you own a newer car or want to maximise the long-term value of your vehicle, AAA's advice is clear: pay the extra money for the extra protection.