In America, the rule is that they're supposed to charge you for parts and for the regular number of labor-hours that job usually entails. A "Master Book" lists all of the typical services and the number of hours those services are supposed to be billed for. Dealerships are supposed to set a "standard hourly rate." Unfortunately. Service writers have a wide discretion on what they can charge. So let's say the typical labor rate is around $250 an hour. And let's say the book states an oil change is a 2 hour affair. The dealership will charge you $500 or so for the labor. Possibly more if they can find some other way to pad the hours. Then you have to pay for parts. Parts has no rules. A dealership can charge whatever markup they want on parts. So for instance, at my Mercedes dealership, the parts cost significantly more, about 150% to 250% the normal "manufactured suggested price." For instance, a Mercedes wheel cap used to retail for $17 on Mercedes' website. My dealer charged $37. My dealer also has a Porsche department, and the markups there were even more astronomical when the economy was good. And the markups are slightly lower when the economy was bad. Thus, it can be very inconsistent. A quart of oil, which costs around $5 a quart retail is often marked up to around double at the Mercedes dealer. And I'm told around quadruple at the Porsche dealer. Funny thing, the two dealerships are owned by the same conglomerate, and Porsche and Mercedes both use the same spec Mobil-1 oil. Some clients are stubborn and thus they negotiate on the pricing somewhat, and my service writer is already aware of what I am accustomed to paying. Some new clients are completely unaware, and especially at Porsche, they are fleeced. My dealership is in a more middle-class part of town, but there are dealerships that cater to the wealthier citizens of the area and they take even more advantage I'm told. I don't remember specifics, but I recall seeing other vehicles being serviced and I was amazed, the costs were higher than that of an Aston Martin! Apparently the Aston Martin dealer isn't taking full advantage while the Porsche dealerships were. Car brands need to make servicing costs more public and clearer. It's very opaque now. Especially as electric cars are coming, and electric cars have lower maintenance requirements. But while I bet the Porsche Taycan is amazing, I'm just scared that they'll try to take advantage since the dealership business model at Porsche is to make BIG money in sales and to make even more margins in servicing. Tesla's service model is different; make big margins in sales and make minimal margins in servicing, and even smaller margins in Supercharging - Supercharging costs are so low, that they don't even fund the expansion of superchargers (superchargers are Tesla gas stations that offer high speed electric charging). Although the servicing costs may change one day at Tesla if they decide they want to make more money off it, since very few places can service a Tesla vehicle.