One school of thought says that cars are expensive and oil is cheap, so change it a lot. Another says, new oils are so much better than in the past this is not necessary. Since I started driving when oil was less than optimal (people put a quart of transmission fluid in with parrafinic base stock oils to hold down the sludge) I do the 3,000 miles routine so I can sleep at night.
These days, the companies that do UOA will look at your oil and tell you whether you need to change more often. So, a few bucks well spent might be the ticket.