Your performance will not improve if your Toyota door mirror is functioning, but the driver and passengers will be safe while traveling on the road. There is a door mirror on both sides of your Toyota when it comes from the factory. The purpose of the Toyota door mirror is to help the driver of the vehicle to know just what is behind them and could be approaching them from their rear. This makes it possible to maneuver in traffic with greater confidence that changing lanes will not get the vehicle into an accident. To make this possible the angle and pitch of the reflective portion of the door mirror must be adjusted correctly so the driver can view the area behind their vehicle where the other cars might be present. The reflective portion of the door mirror should last the lifetime of the vehicle. What generally wears out is the electric motor that adjusts the angle and pitch of the mirror so the driver can view the area of the road behind them they need to see. Since the mirror on the door is actually attached to the door shell on your Toyota, access to the inner door panel is required for this body component can be replaced. Before the battery is disconnected, the door window glass should be raised to its upper most position. This will give a person access to not only the electrical wires that connect and control the door mirror but also the mounting bolts. It is advisable to have an assistant in this repair procedure. This way when taking off or mounting the new mirror it cannot damage the finish on your Toyota. The only alternative is to have really long arms.