Audi, BMW, and Porsche are common offenders.

Unless you’re the lucky owner of one of the most reliable cars ever made, chances are you’ll inevitably start to visit your mechanic more often once you’ve gone beyond the five-year mark or gone over 60,000 or so miles.

Some problems are more common than others, though. For instance, an air conditioning compressor or alternator are two parts that simply won’t last forever. Consumer Reports has just revealed the results of a study that looks into how much common parts will cost to replace on various cars and SUVs. As you can imagine, German luxury vehicles did not fare well at all.

Data was used from RepairPal to compile an average repair cost per part along with the worst offenders. Let’s start with that AC compressor: the average repair cost was $1,211 but the BMW 750Li was by far the worst with a staggering cost of $4,453, followed by the Lexus GS450h at $3,693 and the Mercedes-Benz E400 at $3,684.

Another BMW, the M760i xDrive, requires $2,669 to replace the alternator, behind only the Porsche Cayenne ($2,810) and far above the average for all cars ($825). The replacement of a fuel pump costs an average of $1,135 for all cars but both the Lexus IS F and LS460 will require you to part with over $3,700 for the same repair.

Another unavoidable repair down the line is the starter, which had a reasonable average cost of $630. However, the Audi RS5 registers a far higher $2,708 for this repair, followed by the Mercedes-AMG GL63 on $2,695.

In the case of the RS5, the starter is challenging to access and this contributes to the exorbitant cost. Certain Audis were generally also more expensive than most when it came to timing belts and water pumps.

While most vehicles on the list were high-priced models, the BMW X1 made an appearance for an especially pricey serpentine belt replacement of $541, far above the average of $140. The list also reveals that more complex hybrids or low-volume performance cars that don’t share parts with other models have elevated repair costs. On the other hand, most buyers who can afford a BMW M760i at over $150,000 probably won’t have any sleepless nights over a $2,669 alternator replacement. If you’re thinking of buying a second-hand German luxury car, these results might just make you think twice.