Q. How often should I change my oil? Every three months or 3,000 miles, right?

A. No. That's the old standard that oil change shops continue to promote.

The automakers say newer cars and trucks can go much further than that.

Toyota, for example, recommends six months or 5,000 miles for its recent models. Ford and Chrysler recommend every 7,500 miles. Check your owner's manual to see how frequently it says your car or truck needs one.

Honda and General Motors (the maker of Chevrolet, Buick, Cadillac, Saab, GMC, Pontiac and Saturn) have even stopped making specific recommendations for most of their cars and trucks.

They're installing sensors that measure oil temperatures and engine revolutions to calculate oil life and activate a warning light when it's time for a change.

GM's data indicate that those vehicles are going an average of 8,500 miles between oil changes, and that some have gone as far as 15,000 miles without doing any damage to the engines.

How's that possible?

Motor oils are better. They're being made with higher-quality base oils and better additives that allow them to lubricate longer without breaking down into sludge, which can block oil passages and ruin your engine.

Engines are better, too. Electronic ignition systems and more precisely manufactured parts make cold starts and higher operating temperatures less wearing on your oil.

Changing your oil less is a good way to save money. Ford estimates that typical drivers can save $600 over five years if they do it every 7,500 miles instead of every 5,000 miles.

You're also doing the environment a favor by creating less waste oil.