The cost-effectiveness of using Dexos-specification motor oil in a vehicle depends largely on the vehicle's manufacturer, the year it was manufactured and the type of use the vehicle normally sees. For instance, as of 2015, General Motors requires that individuals use Dexos-specification motor oil in GM vehicle models manufactured in 2011 and later. Anyone who fails to use Dexos-specification motor oil is in danger of having the vehicle's engine warranty voided.
The use of synthetic or synthetic-blend motor oil that meets Dexos specifications has certain advantages over conventional motor oil. Typically, synthetic and synthetic-blend motor oils resist heat and shear better, and they provide better engine lubrication than conventional motor oils. Vehicle engines that see severe use can benefit from synthetic-type motor oil. Examples of severe engine use includes frequent instances of engine idling, "stop-and-go" type driving experienced in cities, and trips that average five miles or less. Synthetic-type motor oils are also more forgiving when used in engines that do not always see oil changes performed on time.
The use of conventional motor oils is much more appropriate in vehicles that do not specify synthetic motor oil use and see much less severe engine use, such as longer trips of 10 miles or more and an even mix of highway and city driving.