Most oil changes require 4 quarts of oil, but the exact amount depends on the specifications of the vehicle. It is best to consult the owner's manual in order to determine the size of a vehicle's oil reservoir.
The most important part of any oil change is the filter. The filter used on a vehicle goes a long way to preserving the viscosity of the oil being used by removing impurities and sediment from the fuel system and the engine compartment. While it is still a good idea to change a vehicle's oil every 3000 miles, a good filter removes some of the worry if time does not allow for a quick stop at a lube shop.