“There was a time when the 3,000 miles was a good guideline,” said Philip Reed, senior consumer advice editor for the car site Edmunds.com. “But it’s no longer true for any car bought in the last seven or eight years.”  
 
Oil chemistry and engine technology have improved to the point that most cars can go several thousand more miles before changing the oil, Mr. Reed said. A better average, he said, would be 7,500 between oil changes, and sometimes up to 10,000 miles or more.