A typical driver should have a professional install an aftermarket GPS navigation unit in a car, as the process requires making wire connections and finding the correct location for the GPS antenna, but drivers who have the time and ability can perform the installation themselves. Common benefits of professional installations include a warranty and free reinstallation of the factory equipment, if necessary.
Car GPS units are either portable, which don't require installation, or installed in the dashboard. In-dash units are factory-installed, meaning the manufacturer installed the unit in the car, or aftermarket. One advantage of having a professional install an aftermarket unit is that professionals are often able to match the unit to the rest of the car's interior.
Car installation professionals typically offer lifetime warranties on GPS installation, so an owner can take the car back to a professional if anything goes wrong with the GPS unit. If the owner wants to remove the unit and place the factory equipment back in the car, a professional who offers free factory reinstallation can do that for him. This saves the owner time.
The installer typically wires the GPS unit to the car's speed sensor and parking brake. He also finds a location with an adequate signal to mount the GPS antenna.