once they get down to the "wear bars" it is time to replace them.
it's easy and a quick thing you can do to keep yourself involved with your car's maintenance. if it's too high or too low, it can cause trouble for your vehicle. to check your oil, park on level ground and wait until your car has cooled down after driving. find your engine's dip stick, pull it out and wipe it on a clean towel. put it back into it's slot and pull it out again. check the level of the oil at the end of the dip stick. it should be in the area between the two 