main questions are how you drive, were you drive and type of vehical. If you drive short trips all the time and never warm up the engine, change it more often, if you live in a very dirty, dusty area, change it more often. if drive mostly highway you can extend it longer. I feel the biggest problem is not the oil going bad, but what gets in the oil that can cause problems. on todays modern cars i do beleive you can go longer, but alot of people push the issue, but we don't mind putting in new egines for those customers. todays everyday consumers don't check there oil (or any other fluids) between oil changes, so that why i tell my customers to try to change it at 5,000 miles. it's cheap insurance