3.Dealership Recommended Services and Up-Sell; The dealership will have their own list of recommended services, so the best way to avoid these traps is to know your manufacturers recommended service schedule for your vehicle.
A dealer recommended service is something the dealership has created to generate more profits for the company; it's what they think you need based on their professional opinion. Some of the services are on the up and up, but some are downright scams, and are just a waste of money. The best way to avoid being sold a service that you don't need is to check your owner's manual under manufacturers recommended services.
In the maintenance section of the owner's manual, you will find a list of items your vehicle will need to have inspected and or replaced, some of the items are based on mileage, and others based on time and driving conditions. Newer vehicles use maintenance minders built into the vehicles maintenance message system to alert the driver when the vehicle is due for service.
The owner's manual will explain every message in the maintenance message system, so if you are uncertain of what the message means when the light is illuminated on the dash, check the owner's manual, and if you're still unsure, call the dealership and ask them to explain it.
If the dealership is trying to sell you a service that you can't find in your owner's manual, it's a good possibility you don't need it. A good example of a dealership recommended service is a fuel injector service. I have never seen a fuel injector service fix a problem, but I have replaced a bad injector and fixed the problem. In my opinion, a fuel injector service does nothing for your cars fuel mileage or its performance, so if it's not in the owner's manual, question why you need it.
When in Doubt, always refer to your owners manual or maintenance message system
I would be very careful of the dealership up-sell, some up-sells are legitimate, but other up-sells are just ways to scare you into buying more unnecessary work. A lot of dealerships are moving in the direction of automotive flushes like radiator, transmission and brake fluid flushes. In some situations the flushes are necessary, but not as a regular maintenance. Most systems on vehicles are drain and fill, just like your oil, I would never recommend an engine oil flush; it could cause major damage to the engine.
If you stick to the maintenance schedule in your owner's manual, you'll be doing all the maintenance your car needs. Today's vehicles are built to last much longer then the vehicles in the past with far less maintenance, that's why dealerships are making up their own recommended services and maintenance schedules.
Vehicle maintenance costs have been reduced significantly in the past years, they have been just about cut in half compared to the same vehicle built ten years ago, and that really hurts the service end of the dealership. Most manufacturers want to make their profits when you purchase the vehicle, not during ownership, that's why oil changes are now every 5k instead of 3k, and transmission fluid can last up to 100k before changing instead of 30k.
Low maintenance costs are a big selling point when you're car buying, it's great for sales, but bad for the service department, that's why service departments are getting so creative with up-sells, the manufacturers have just about deleted the big maintenance schedules.