I have been an automotive technician going on 34 years. I have worked in many shops and on many makes, models and years of vehicles. I have heard customers complain say their automobiles were running ok before they brought them into the shop; but in reality they were not running right in the first place because they were not maintained like they are suppose to be. Many people don't notice their automobiles are about ready to give them a problem. Your car will run great until it doesn't and not all vehicles will give you a clue they are about to break down or start running badly. It automobiles today aren't like the 50's, 60's and 70's of the past. They are more on the lines of aircraft quality today. Everything is electronically computerized now, so it's impossible to know when one or more of the circuits in the electrical system will malfunction (Fail).
Even in the mechanical areas of the vehicles, it can be difficult to know when it will fail so to avoid these problems, you should take your vehicle in to have it checked out and maintained per factory manufacturers recommendations as your service manuals when you bought the car, truck or van says to. I do know some used cars are missing these service manuals that came with the automobile at one time in the past, so it would even be wiser to at least have the vehicle looked at every 6 months to help eliminate possible break downs and to also save money on parts that could have had a longer life to them if the vehicle was maintained properly.
Remember that these machines you drive are not designed to last forever and due to mass manufacturing not all parts will work as long on one car as they will the other. The parts are not designed to last forever because if you had a car that never needed replacing of parts, the economy would fail in that industrial area and then you would be back to walking or riding a horse. This is just the reality of life. Please take things into consideration that there is no perfection on earth and most technicians do really care about your automobile they are working on and want to fix your problems as quick as possible and do quality work at the same time.
The only way for you to know what us technicians and shop owners go through and the money we spend to keep up with technology and tools is to try doing what we do and then you will know that we are doing our best to help you out and make a living also. Most technicians have to spend at least $1000.00 a month on tools to keep up with the demand. It's non stop and the shop has to invest into the 10's to 100's of thousands just to be able to keep up also and diagnose and repair your automobiles.