A trip to the mechanic is about as enjoyable as a trip to the dentist, except without the cool laughing gas. Most repairs that auto techs recommend are necessary. However, mechanics get paid based on the jobs they do. The more work they perform on your vehicle the more they get paid.
Be wary of routine maintenance pushed by your mechanic when your car is broken down. The factory-recommended maintenance should be performed, but if money is tight, it's an expense that can usually wait until a later time. Car owners should review their owner's manual to keep up with what needs to be done before going to the shop.
Ask if your mechanic is involved with the motorist assurance program (MAP). It's a national organization created to inform the customer on why recommendations were made regarding your vehicle. Ask what repairs are absolutely necessary to fix your car and which ones are just recommendations.
Avoid some suggested add-ons altogether. When purchasing wiper blades or light bulbs at your repair shop, you pay for the part (with a 50% mark up) and the cost to install them. You can purchase the exact same parts at an auto parts store for half the cost, and most stores will install them for you at no charge.
Be informed and ask questions. Don't be pressured into making a purchase by a sales agent. Talk to the technician directly and ask him to explain exactly what needs to be done and the order of importance.