I know that conventional oil is supposed to last 5K-8K miles today but I still change it at 3K or as close as I can get. The 5 quart jug and the filter run $20-$23 total. It's not so much I don't think the oil will last that long but if you are having an engine issue it's a lot better to find the antifreeze/metal/gas etc... in your oil after 3K miles instead of 7K miles.
And I learned from Dodge that their "recommended" oil change interval is 8K under normal conditions and 3K under extreme conditions. If you read the details basically it defines "extreme" as the weather conditions one encounters while driving in North America. So if you use the recommended oil change interval from the manual you were violating the warranty - a huge issue if you had a 2.7 V6 engine.