I was aware of that VW has a reputation of suffering from rusty brake discs and also callipers, something that my car is supposed to be suffering from is callipers corroding, especially in the area where the bleed nipples are. I say that because my car needs to have its brake fluid changed, as it is due for it according to the service history. In fact, it was booked in to be done, but the mechanic said he was unable to undo the nipples due to them rusting in the calliper, and the allocated time caused him to decease any further attempts at undoing them. I suggested that they could perhaps spray them with penetrating fluid and leave it for a few days to soak in, and book the car in again to try again? I was told that would not work in their experience and the only thing that could do was to order up 4 new callipers just in case the nipples broke.
This is still pending along with a slight oil leak which is not bad but will get worse if not attended to, so I intend to get the indie garage where I get my broken front spring replaced to attempt to do these jobs in the near future as I feel that the dealer will not even bother with attempting to get the old nipples out and fit new ones, but will just replace the complete callipers at a greater cost than the indie would.
But my discs are showing any signs of rust anywhere the pads go, they do show signs however at the edge of the disc and the hub, which is normal as the pads do not come into contact there. But my car does get used almost daily, and Monday to Friday it is used at least twice a day taking one of my sons to his brother's as they work together and go in the same car 3 days a week, the other 2 days I have to take him all the way as his older goes to the gym early in the morning on those days. So that keeps my discs nice and shiny, so rust doesn't get a chance to build up.