Though typically not one of the major factors for consumers when purchasing a new vehicle, residual value is an important part of the car-buying process. According to Forbes, some cars retain as much as 60 percent of their value after five years, however many can drop to as little as 20 percent of the original value in the same span. Here is a list of the 10 cars with the best residual value:1. BMW 6 Series2. BMW 7 Series3. Honda Accord Hybrid4. Infiniti G35 Coupe5. Lexus GX 470 (SUV)6. Mercedes-Benz SL5007. Mini Cooper8. Porsche 9119. Scion tC10. Toyota PriusAll of these cars should maintain 50-55 percent of their current value, according to the report. Many dealers take note of depreciation, so when a buyer comes in buying a car such as these, dealers call it “buying right.” As in any market, supply and demand have a large impact in how a car will be priced down the road. If there is high demand, chances are the car will hold on to much of its value. The opposite is true as well.Some of the keys to buying right are in the package that is purchased. The report recommends sticking with more conventional colors like black, white or silver. Add-ons such as power windows, cruise control and alloy or premium wheels not only add value later on, but the absence of those can subtract from the residual worth, according to the report.Other items like keyless entry, leather interior and an engine upgrade (if possible) may not have a negative effect if left out of the purchase, but they will definitely improve the value when included.