The additives that manufacturers add to motor oil break down over time, making oil changes necessary, according to HowStuffWorks. The oil also picks up dirt and debris from the wear of the engine. While the filter removes foreign material for a while, if it gets plugged the oil bypasses it.
For years, auto manufacturers recommended changing oil every 3,000 miles, but as of 2015, most manufacturers have increased the oil-change interval to 7,500 or more miles, according to Cars.com. One way to be certain of the manufacturer's recommendation for a certain vehicle is to check the owner's manual. While checking the interval, it is a good idea to determine the type of oil the manufacturer recommends.
When operating a vehicle under severe conditions, Cars.com indicates most manufacturers recommend more frequent oil changes. Examples of severe conditions include frequent towing, stop-and-go traffic and driving in extreme temperatures. To help owners determine when to change their oil, some manufacturers, including Ford and GM, include oil-change indicator lights. These lights use information from the vehicle's on-board diagnostic center to recommend oil changes. Many drivers report following the oil-change indicator light allows operation of the vehicle safely beyond the 7,500-mile mark.
Regardless of the number of miles driven, GM recommends changing the oil at least once per year, according to Cars.com. The longer period between oil changes places the responsibility on the driver to check the oil level frequently to ensure it remains full.