You can easily find a lot of forums on the Internet that discuss automotive electronics and numerous sites that publish information about this specific field. People who have opinions about who should install car electronics are quite divided in their answers. It's not an easy question to resolve because it can depend on several factors - the familiarity of the car owner with his or her car's electrical system, the make and model of the car, and the kind of electronic equipment that needs to be installed.
Obviously not everyone bothers to be knowledgeable about the inner workings of their car's electrical system. The most that can be expected of a typical car owner to learn is how to replace or recharge the car batteries. Their needs and wants however will often exceed their understanding. Thus the question comes up when they finally get a hankering to put a subwoofer, a DVD player, or a satellite receiver in their cars. An absolute beginner in car electronics or someone who finds electronics in general to be as esoteric should start by reading the owner's manuals, researching tips and downloading circuit diagrams. This can already help a lot for those who insist on taking the do-it-yourself route. But no amount of theory or book smarts is going to make up for experience which is what an authorized professional has loads of.
Old cars have simpler electrical systems. Installing a radio in one would most likely only require locating the proper power supply wires, connecting the ground wire and securing all these connections so they don't dangle or protrude and cause accidents. Modern cars, however, have far more complex circuitry. They now have computer systems that control and automate everything from the engine to the power windows. What would have been a simple splicing job in an old model car would be unthinkable in a modern car. One could easily short circuit the wiring, damage the equipment to be installed or fry the car's electrical system. Even the initial task of locating the proper wires and terminals may already be a chore in itself as dashboards in new cars are more seamlessly mounted and it would take some special tools just to open the panels without destroying them.
Typical consumers upon hearing the phrase "car electronics" would commonly think about car audio equipment - radios, CD players, amplifiers and speakers. But there are actually a lot of other types of electronic devices that can be installed in an automobile. There are remote automatic ignition systems, anti-theft systems, radio satellite receivers and GPS systems. Each of these of course comes with their own components and unique procedures for set-up. One issue that will quickly arise when installing a third party car electronic device is incompatibility. There needs to be a good match between the car model and the device.
To make the right decision on whether to do an installation yourself or hire a professional, you will have to make an honest and accurate assessment of the factors outlined above. If you think you have the adequate know-how, are willing to put in the time and effort, and are capable of facing the risk of voiding the car's and the electronic equipment's warranty, then go ahead--pull up your sleeves. Hiring a professional may seem like the convenient and safe recourse. But keep in mind that not everyone who accepts money to do a job is actually an expert. Choosing to a hire a professional then entails finding one that's credible. Car electronic equipment warranties will often be considered void by most manufacturers if they weren't installed by accredited dealers or authorized professionals.