Do you simply take it to any mechanic who lives closest to you? Most people lose a lot of money because they use dishonest mechanics who will make money off you whether there's a problem with your car or not. A few actually change you new Car Parts with old ones to ensure that you do more business with them in future. How should you choose the right mechanic? Ask your friends to recommend the best. That way you can't go wrong and you won't get ripped off either.
If you have an old, cheap car, take it to a close mechanic that seems more honest than the rest of them. You will only know this through experience or if someone you trust tell you too. If you have a better car take it to the official representative because it will pay off in the long run. Even in the official representative ask a lot of questions and look informed or they can scam you there too.
I own a car repair shop. Well, I am the general manager, but it's a family business, so I can as well say, that I own it. I suggest everyone to take their cars to a legit car repair shop, not just the closest car mechanic. They may seem friendly and trying to 'help you out', but quite a few of them will rip off even their closest friends. If they sense that your mechanical knowledge is very limited, then they'll try to 'make money' off you. Better go to a legit car repair shop, that will list everything they repaired, every changed part and will show cost of everything. Some people think we make lots of money off car parts, but believe me most repair shops barely make any profit from that.
We are SO lucky! We have a regular shop we go to. It's a family business, and they are GREAT! They stand behind their work, and their products, and won't rip off people. If they don't find anything wrong, they don't charge! That is VERY rare! We have four in the family going there, so we are regulars what with all the regular maintenance for all. Having someone you trust work on your vehicle is HUGE! Find someone and stick with them. Integrity is rare, once you find it, support them.
I always work with people based on recommendation. So if my car is in need of repairs I ask my friends for mechanics that they had a great experience with, regarding money and repairs. The only time I'd risk going to someone I don't know anything about is if my car breaks in the middle of a trip since I have no other options. Even then, I might stop some locals and ask for a recommendation.
@Denis Hard Actually, you don't need friends. You can just do research with reputable sites like Angie's List. Also, I'm sure there are some online complaint boards where you could interact with real past or present customers of various auto mechanics. Oh, and another thing, do not expect something for nothing. Note, a bargain is something to look for, but expect a good job might cost more.